Definitions-2

No	Term	Definition
251	Eruption cyst	An soft tissue odontogenic cyst with the histologic features of a dentigerous cyst that surrounds a tooth’s crown that has erupted through bone but not soft tissue and is clinically visible as a soft fluctuant mass on the alveolar ridges. Also known as Eruption hematoma
252	Eruption sequestrum	A small spicule of calcified tissue (bone) that is extruded through the alveolar mucosa often that overlies an erupting molar.
253	Erythema	Refers to an abnormal redness.
254	Erythematous	A change in the area of pathology caused by a redness of the tissue due to engorgement of the capillaries in the region. Usually erythematous lesions blanch on diascopy.
255	Erythroleukoplakia	Refers to a reddish white, raised, unscrappable patch more than 5 millimeter in diameter and cannot be attributed to any cause other than the use of tobacco, with reddish areas representing epithelial cells that are so immature that they can no longer produce keratin.
256	Erythroplakia	Refers to reddish, raised, unscrappable patch more than 5 millimeter in diameter which cannot be attributed to any other cause other than the use of tobacco, the definition carrying no histopathological connotation. (Or ) A predominantly  lesion of the oral mucosa that cannot be characterized as any other definable lesion; some leukoplakia will transform in to cancer. (Axell T, 1996)
257	Esophageal webs	Refers to the abnormal fibrosed bands of tissue in the esophagus in Plummer – Vinson syndrome leading to dysphagia.
258	Etiology	The study of the factors that cause disease and their introduction to the host.
259	Ewing sarcoma	A rare malignant bone neoplasm of uncertain cell origin in young patients, the lesion being composed of anaplastic small, dark, round cells containing glycogen granules and . intermediate filaments often exhibiting translocation t(1122)(q24,q12)
260	Exanthems	Eruptions of skin accompanied by inflammation.
261	Exophytic	Refers to an outwardly growing lesion.
262	Exostoses or Exostosis	An exophytic nodular benign growth of dense cortical bone commonly located on maxillary or mandibular buccal alveolar bone, usually in the bicuspid / molar area.
263	Expansile	Refers to the ability of a lesion of being extended or expanded.
264	Expressivity	In clinical genetics, the degree of clinical manifestation of a trait.
265	Extrinsic stain	Superficial stains on the external surface of teeth like tobacco, coffee, drugs etc.,
266	Exudate	Fluid composed of cells, proteins, and solid materials that pass through vessel walls into adjoining tissues; may leak from incisions or sites of infection or inflammation to form a clot.
267	Facial paralysis	Is an acute, often unilateral paralysis of the facial musculature with no proven cause.
268	Facies	The appearance of the face.
269	Fever	A pathological elevation of body temperature to greater than the normal of 98.6°F (37°C).
270	Fibrin	An insoluble protein that plays a vital role in clotting mechanism of blood.
271	Fibroepithelial polyp	A less common fibrous hyperplasia of connective tissue occurring in the hard palate beneath a maxillary denture. It presents as a flattened pink mass attached to the palate with a stalk.
272	Fibroma	A reactive hyperplasia of fibrous connective tissue that evolves in response to chronic irritation in which there is extensive elaboration of collagen resembling scar tissue.
273	Fibromatosis	Are a broad group of fibrous proliferation with diffuse infiltrative proliferation of fibroblasts and mature collagen occurring within the soft tissues of the head and neck in young patients. Their biological behavior is between benign fibrous lesion and Fibrosarcoma.
274	Fibro-osseous lesions	They comprise a diverse group of processes that are characterized by replacement of normal bone by a fibrous connective tissue containing newly formed mineralized products that do not exactly resemble the tissue it replaces.
275	Fibrosarcoma	Refers to the malignant neoplasm of fibroblastic cells.
276	Fibrous dysplasia	A developmental asymptomatic regional alteration of fibro-osseous lesion of bone in which the normal architecture is replaced by fibrous tissue and nonfunctional trabeculae-like osseous structures; lesions may be monostotic or polyostotic, with or without associated endocrine disturbances.
277	Fibrous histiocytoma or Dermatofibroma	They are a diverse group of soft tissue benign tumors that exhibit both fibroblastic and histiocytic differentiation.
278	Field cancerization	The tendency of oral cancer to develop multiple mucosal cancers as primary and reflects the effect of diffuse exposure to local carcinogens that increases the malignant transformation potential of all exposed epithelial cells.
279	Firm	Relatively solid, compact, or unyielding to pressure or touch.
280	Fissural cysts	Originally believed to arise from cystic degeneration of epithelium remnants entrapped along lines of fusion of embryonic growth processes.
281	Fissure	A narrow slit or cleft.
282	Fissure tongue	A developmental anomaly of tongue observed as deep grooves in dorsum of tongue which cause no adverse consequences other than being a collection site for food debris and colonization site for Candida albicans. Caused by improper fusion of the lateral swellings.
283	Fistula	A drainage pathway or abnormal communication between two epithelium-lined surfaces due to destruction of the intervening tissue.
284	Fistula, congenital of lower lip	Are rare congenital invaginations of the lower lip that arises from persistence of the lateral sulci on the mandibular arch.
285	Fistula, oroantral	Is a fistula connecting the maxillary sinus and the oral cavity formed usually as a complication of a extraction of upper molar.
286	Fluctuant	A wavelike motion felt on palpating a cavity with non-rigid walls, especially one containing fluid.
287	Fluoride mottling	A condition of enamel hypoplasia characterized by white chalky spots or brown staining and pitting of teeth due to an increased ingestion of fluoride affecting enamel matrix formation and calcification by impairment of ameloblastic function.
288	Fluorosis	An enamel defect resulting from ingestion of fluoride in excessive quantities. It causes permanent hypomaturation of the enamel with increased surface and sub- surface porosities.
289	Foam cells	Are lipid laden phagocytes that appear as empty in H&E section as lipids are lost during processing. The presence of foam cell with macrophage and numerous inflammatory cells in the vincity indicates that there is foreign body reaction present.
290	Focal epithelial hyperplasia	Is a virus induced, multiple, soft non-tender, flattened plaques and papules that are localized proliferation of oral squamous epithelium affecting children.
291	Focal osteitis	Also known as dry socket. A complication of traumatic tooth extraction, resulting in a dry appearance of the exposed bone in the socket, due to disintegration or loss of the blood clot.
292	Follicular cyst	Also known as dentigeous cyst. A common developmental type of odontogenic cyst associated with unerupted teeth and is caused by fluid accumulation between the reduced enamel epithelium and the enamel surface, resulting in a cyst in which the crown is located within the lumen and root(s) outside.
293	Forchheimer’s sign	Oral lesions of Rubella. They consist of small, discrete, dark red papules usually found in soft palate and rarely in hard palate. These papules coincide with the appearance of exanthematous rashes of the skin.
294	Fordyces granules	They are collection of ectopic sebaceous glands that occur in various locations within the oral cavity.
295	Foreign body granuloma	A granuloma reaction to foreign materials in the connective tissue which are too large to be ingested by either host defense cells.
296	Fourniers molars	See mulberry molars
297	Frenal tag	A redundant piece of mucosal tissue that projects from the maxillary labial frenum.
298	Frictional keratosis	A nonspecific, trauma induced whitish unscrappable hyperkeratotic lesion.
299	Fusion	Is defined as a single enlarged tooth or a two joined teeth in which the tooth count reveals a missing tooth when the anomalous tooth is counted as one.
300	Gardner syndrome	A rare autosomal dominant disease characterized by gastrointestinal adenomatous polyps, multiple osteomas and soft tissue tumors such as cutaneous epidermoid cysts and fibromas.
301	Gargoyle cell	In Gauchers disease, a most common lipid reticuloendotheliases caused by a lack of enzyme glucocerebrodiase resulting in accumulation of glucocereamide within lysosomes of the cells of macrophage or monocyte lineage and the cytoplasm resembles a wrinkled silk appearance is called the Gargoyle cell.
302	Garrè osteomyelitis	An unusual reaction of the periosteum to a chronic inflammation usually in the posterior mandible of young patients as a periosteal hyperplasia demonstrating an onion skin like reduplication of cortical plates.
303	Gaucher’s disease	The most common lipid reticuloendotheliases caused by a lack of enzyme glucocerebrodiase resulting in accumulation of glucocereamide within lysosomes of the cells of macrophage or monocyte lineage and the cytoplasm resembles a wrinkled silk appearance.
304	Gemination	Is a single tooth germ splits completely or partially, forming two separate crowns. Also defined as a single enlarged developmental anomalous tooth in which the tooth count is normal when the anomalous tooth is counted as one.  The tooth usually has a single root and root canal; also called twinning.
305	Genetic heterogeneity	Having more than one inheritance pattern.
306	Geographic tongue	Is a common anomaly of tongue with unknown etiopathogenesis that presents as multiple, sensitive, irregularly shaped erythematous patches on the tongue with arcuate white rims that enlarge and change shape daily.
307	Ghost cells	They are the altered epithelial cells which are eosinophilic, with absence of nuclei but retaining the basic cell outline within the epithelial component of calcifying odontogenic cyst.
308	Ghost teeth	A localized, nonhereditary, developmental anomaly affecting the one or several adjacent teeth in which the enamel and dentin are thin and irregular and fail to adequately mineralize; surrounding soft tissue is hyperplastic and contains focal accumulations of spherical calcifications and odontogenic cell rests.
309	Gingival cyst of the adult	A small developmental odontogenic cyst of the gingival soft tissue derived from the rests of the dental lamina, containing a lining of embryonic epithelium of cuboidal cells and distinctive focal thickenings similar to the lateral periodontal cyst.
310	Gingival cyst of the newborn	Uncommon superficial raised nodules on edentulous alveolar ridges of infants that resolve without treatment, derived from rests of the dental lamina and consisting of keratin-producing epithelial lining.
311	Globulomaxillary cyst	A developmental fissural cyst that arises from epithelium entrapped during fusion of the globular portion of medial nasal process with maxilla, commonly arising between maxillary lateral incisor and the canine with inverted pear shaped radiolucency. [ The origin is now considered as odontogenic cyst than a fissural cyst]
312	Glossodynia	Or Glossopyrosis
313	Glossopharyngeal neuralgia	Is the neuralgia of the ninth cranial nerve with sharp intense lancinating pain with abrupt onset and short duration along the area of innervation by the ninth cranial nerve.
314	Glossopyrosis	Refers to a painful or tender or burning sensation of tongue with uncertain causes that includes infections, malnutrition, deficiency status ,underlying endocrine disturbances etc
315	Gorlin cyst	A rare, well-circumscribed, solid or cystic lesion derived from odontogenic epithelium that superficially resembles follicular ameloblastoma but contains "ghost cells" and spherical calcifications.
316	Gorlin sign	Is the ability of a subject to touch the tip of the nose wit the tip of the tongue. Although a common ability it is most commonly observed in patients with Ehler-Danlos syndrome.
317	Graft Versus Host disease	It occurs in recipients of allogenic bone marrow transplants. With the failure of immunosupression or the graft being immunologically active they are perceived as foreign body and resulting in a debilitating immunologicalreaction called Graft Versus Host disease.
318	Granular cell tumor	Refers to a submucosal mass consisting of diffuse sheets of large cells of either nerve or muscle origin with a cytoplasm of densely packed eosinophilic granules (lysosomal bodies) and commonly found in the dorsal surface of the tongue.
319	Granuloma	It refers to a mass of inflammatory tissue consisting of a central collection of macrophages, often with multinucleated giant cells, surrounded by lymphocytes. The lesion is essentially a reactive one with vascular proliferation and a peripheral fibrous tissue to localize the reaction.
320	Granulomatous	It refers to a well-defined area that has developed as a reaction to the presence of living organisms or a foreign body. The tissues consist primarily of histiocytes and the presence of epitheioid cells.
321	Gumma	The scattered foci of granulomatous inflammation presenting as an indurated, nodular, ulcerated lesion often associated with tissue destruction in tertiary syphilis is gumma.
322	Haemangioendothelioma	Is a term used to describe vascular tumors with microscopic features intermediate between those of Hemangiomas and angiosarcomas.
323	Hairy tongue	Refers to the developmental abnormality of tongue with marked accumulation of keratin on the filiform papillae of the dorsum tongue resulting in hairy appearance and discoloration of the tongue
324	Halo nevus	Is a type of melanocytic nevus that has a pale hypopigmented border probably as a result of the nevus cell destruction by the immune system .
325	Hamartoma	A non-neoplastic malformation that present as a mass of disorganized tissues indigenous to that particular site.
326	Hamartoma	Is a developmental tumor like but non neoplastic developmental malformation native with that area of body in which it is formed. Often present at birth, growth persists till physiologic growth stops and essentially benign.
327	Hand –Schuller- Christian disease	A chronic disseminated form of langerhans cell disease involving bone, skin and viscera, characterized by proliferation of histiocyte like Langerhans cells often affecting children.
328	Hansen disease	Is the other name of leprosy caused by M. leprae.
329	Haploid	A cell with a single set of chromosomes, like a gamete.
330	Heck’s disease	See Focal epithelial hyperplasia
331	Hemangioma	A benign proliferation of large (cavernous) or small (capillary) vascular channels occurring commonly in children with individual lesions having variable clinical courses.
332	Hemangiopericytoma	Is a rare, slow growing, painless, benign neoplasm that is derived from the cells whose processes encircle the endothelial cells of capillaries seen most commonly in adults. The stag horn appearance is observed in histopathology.
333	Hematoma	A large ecchymosis or bruise caused by the escape of blood into the extra vascular tissues. Hematomas are blue on the skin and red on the mucous membranes. As hematomas resolve they may turn brown, green, or yellow.
334	Hemifacial atrophy	Or Romberg syndrome/Parry Romberg syndrome. An uncommon developmental degenerative condition characterized by atrophic changes affecting one side of face. The cause for this condition is obscure
335	Hemifacial hyperplasia Or Hemifacial hypertrophy	A rare developmental anomaly characterized by unilateral enlargement of the body. It is usually more of hyperplasia than hypertrophy.
336	Hemolysis	The term refers to the disintegration of elements in the blood. A common form of hemolysis occurs during anemia and involves lysis or the dissolution of red blood cells.
337	Hemophilia	Refers to a variety of bleeding disorders associated with a deficiency (usually genetic) of any one of the clotting factors of blood.
338	Hepatomegaly	Enlargement of the liver.
339	Hereditary	Transmitted or transmissible from parent to offspring; determined genetically.
340	Hereditary benign intraepithelial dyskeratosis	A rare autosomal dominant inherited genodermatosis showing thick white corrugated white plaques in buccal mucosa in childhood. Additionally ocular involvement is common.
341	Hereditary gingival fibromatosis	Is a slowly progressive gingival enlargement caused by the collagenous overgrowth of the gingival fibrous connective tissue. Often occurs with syndromes and associated with hypertrichosis, craniofacial deformities, epilepsy and mental retardation.
342	Hereditary hemorrhagic telangiectasia	Is an uncommon mucocutaneous disorder, inherited as a autosomal dominant trait, with numerous vascular abnormalities, the most common being small collections of dilated capillaries (telangiectasia)
343	Herpes gladiatorium	The herpes virus infection spread through contact sports such as rugby, wrestlers, contaminating through areas of abrasion.
344	Herpes labialis	The recurrent form of the herpes simplex virus 1 along the vermillion border and adjacent skin of the lips. Also known as cold sore or fever blister.
345	Herpes zoster	The painful reactivation of the varicella zoster virus that has resided in the dorsal spinal ganglia, along the distribution of the affected sensory nerve forms clusters of vesicles on an erythematous base is referred as herpes zoster.
346	Herpetic paronychia or Herpetic whitlow	A less common site of infections of the human simplex virus -1 along the thumbs or fingers.
347	Heterozygote	An individual with two different genes at the allele loci.
348	Histicytosis X	A probable neoplastic proliferation of Langerhans type of histiocytic cells with a wide spectrum of biological behavior ranging from a single lesion of the mandible to diffusely distributed bone lesions in combination with organ and other soft tissue lesions; consists of S-100 positive histiocytes containing Birbeck granules and accumulations of eosinophils.
349	Homozygote	An individual having identical gees at the allele loci.
350	Hormone	A chemical substance produced in the body that has a specific regulatory effect on certain cells or a certain organ or organs.
351	Howell – Jolly bodies	A red blood cell abnormal feature observed in peripheral smear of pernicious anemia.
352	Humoral immunity	Immunity in which antibodies play the predominant role.
353	Hurler cell	See Gargoyle cell
354	Hutchinson’s freckle Or Lentigo maligna	Occurs mostly on sun exposed surface area of elderly persons and represents a melanoma in purely radial growth phase.
355	Hutchinson’s incisors	Screwdriver-shaped central incisors seen in congenital syphilis.
356	Hyerplastic gingivitis	Focal or generalized fibrous hyperplasia of the marginal gingiva with an associated chronic inflammatory response.
357	Hypercementosis	Excessive deposit of cementum on root surface.
358	Hyperchromatic	Staining more intensely on comparison with normal. Inflammatory cells staining are taken as the standard.
359	Hyperdontia	A condition characterized by extra teeth in supplement to the normal set of teeth.
360	Hyperkeratosis	Excessively thickened layer of the stratum corneum. A feature of epithelial dysplasia.
361	Hyperpigmentation	Refers to excessive melanin pigmentation. Multiple causes including postinflammatory, smoking, drugs etc.
362	Hyperplasia	An increase in the size of a tissue or organ due to an increase in the number of constituent cells.
363	Hypertrophy	An increase in the size of a tissue or organ due to an increase in the size of constituent cells.
364	Hypocalcification	Less than normal amount of calcification.
365	Hypochromic Stained less intensely on comparison with normal. Inflammatory cells staining are taken as the standard.
366	Hypodontia	The congenital absence of one or more (But less than 6) teeth as a result of agenesis.
367	Hypophosphatasia	An osteodystrophy with genetic metabolic disorder of bone mineralization caused by a deficiency in alkaline phosphatase in serum and tissues. The condition is characterized by skeletal defects resembling those of rickets.
368	Hypophosphatemia	Deficiency of phosphates in the blood.
369	Hypopigmentation	Decrease in pigment production as compared to the adjacent normal tissue.
370	Hypoplasia	Reduction in size of tissue due to a lesser number of cells. May be physiology or pathology.
371	Hypotrophy	Decrease or reduction in size of cell in a tissue or organ.
372	Idiopathic bone cavity	Or simple bone cyst results due to a trauma to bone that is insufficient to cause fracture resulting in an intraosseous haematoma which does not undergo organization but liquefies to form a cyst.
373	Immune complex	A combined product of antibody and antigen.
374	Immune reaction	A protective response of the host to a specific invading pathogen or toxins secreted by it.
375	Immunodeficiency	A deficiency of the immune response caused by quantitative or qualitative defect of the lymphoid cells.
376	Immunoglobulin	Or Antibody.  Are proteins synthesized by plasma cells in response to a specific antigenic stimulus. They are important for humoral immune system.
377	Impacted teeth	Those teeth that are formed but cannot erupt in to oral cavity because of a physical obstruction or lack of space.
378	Impetigo	A superficial infection of skin occurring in endemic among children and caused by Sterptococcus pyogenes and staphylococcus aureus. The disease manifest as a vesicle  or bullae that rupture with a crusting.
379	Incisive canal cyst or nasopalatine duct cyst	An intraosseous developmental cyst of the midline of the anterior palate, derived from the islands of epithelium remaining after closure of the embryonic nasopalatine duct. Appears as a heart shaped radiolucency between roots of maxillary incisors.
380	Incontinentia pigmenti	A rare inherited genodermatoses with female predilection and has a high risk of malignancy occurring in infancy. May present as a vesicular, verrucous, hyperpigmentation and or atrophic stage.
381	Induration	Characterized by being hard; an abnormally hard portion of a tissue with respect to the surrounding similar tissue.. Often used to describe the feel of locally invasive malignant tissue on palpation.
382	Infection	Invasion by pathogenic microorganisms causing disease by local cellular injury, secretion of a toxin, or antigen-antibody reaction in the host.
383	Infectious mononucleosis	Is a symptomatic disease caused by Epstein Barr Virus, spread by intimate contact producing low grade fever, lymphadenopathy, pharyngitis, tonsillitis and rarely hepatosplenomegaly.
384	Inflammatory fibrous hyperplasia	An asymptomatic reactive proliferation of fibrous connective tissue with an associated chronic inflammation in response to chronic injury such as ill fitting denture.
385	Inflammatory papillary hyperplasia	A reactive tissue growth often associated with a denture that is poorly maintained and worn always.
386	Inflammatory reaction	A defense mechanism to an invading pathogen or toxins which includes repair and destruction; prepares tissue for healing and controls spread of infection.
387	Intradermal nevus	In latter stages of compound nevus, the nevus cells are restricted to underlying connective tissue of skin after which the pigmentation is reduced, surface becoming papillomatous with hairs appearing from centre of the lesion.
388	Intraductal papilloma	An ill defined salivary gland tumor common in adults as a unicystic, dilated structure submucosally with papillary projections in to the lumen of the duct.
389	Intramucosal nevus	The pigmented nevus is characterized by a proliferation of nevus cells microscopically within the underlying connective tissue. Mucosal counterpart of intradermal nevus.
390	Intrinsic stain	Deeply formed stains in the inner layers of the dentin and pulp.
391	Invasion	The infiltration and active destruction of surrounding tissues.
392	Inverted ductal papilloma	A rare minor salivary gland tumor presenting as a asymptomatic nodule that is made up of proliferation of squamoid epithelium with multiple bulbous papillary projection that fill the lumen.
393	Involcrum	New reactive bone formation by the periosteum, usually in cases of osteomyelitis.
394	Iron deficiency anemia	Is the most common cause of anemia which forms when the supply of iron by the body cannot keep with the pace of need for iron in the production of red blood cells. The erythrocyte appears as hypochromic and microcytic in nature.
395	Irreversible pulpitis	A severe inflammation of pulp, progresses from reversible pulpitis, that cannot be restored to its original constituents nor repairable.
396	Irritation fibroma	A reactive hyperplasia of fibrous connective tissue that evolves in response to chronic irritation (ill fitting denture, sharp teeth) in which there is extensive elaboration of collagen resembling scar tissue.
397	Ischemia	A deficiency of nutrition and oxygen to a part of the body usually due to constriction or blockage of a blood vessel.
398	Jaffe-Lichtenstein syndrome	A syndrome characterized by polyostotic fibrous dysplasia of the skeletal system and cafe-au-lait spots.
399	Jaundice	A diseased condition of the liver due to the presence of bile pigments in the blood and characterized by yellowish staining of the eyes, skin and body fluids.
400	Junctional nevus	The pigmented acquired nevus that is characterized by a proliferation of nevus cells microscopically within the basal cell layer of the surface epithelium, named because microscopically appears at the junction of epithelium and connective tissues.
401	Juxta organ of Chevitz	Is a cluster of nests of squamous epithelial cells found in sites of inferior alveolar nerve block and intimately associated with myelinated nerves.
402	Kaposi sarcoma	A unique form of angiosarcoma that occurs in elderly and HIV-positive patients and has a predilection for the palate, associated with Human Herpes virus -8.
403	Karyotype	A photomicrographic representation of a person's chromosomal constitution arranged according to the Denver classification.
404	Keratoacanthoma	A benign, self limiting, endophytic epithelial growth appearing as a well circumscribed keratin-filled crater on sun-exposed skin; often mistaken for well differentiated squamous cell carcinoma.
405	Keratoconjunctivitis sicca	The chronic, systemic autoimmune disorder that principally involves the salivary, lacrimal and eyes is the Sjogren’s syndrome. The effect of such a condition on eye is keratoconjunctivitis sicca.
406	Keratotic	A condition of the skin characterized by the presence of increased keratin growths. On the oral mucous membrane, keratotic tissue usually looks white; the term also refers to a thickening of the outer layer of the oral epithelium.
407	Kissing lesion	The central papillary atrophy of tongue is an chronic low grade candidiasis, from which the infection spreads to the palate when the tongue is at res due to the intimate contact.
408	Kissisng disease	See Infectious Mononucleosis
409	Klestadt cyst	A developmental cyst of the soft tissue of the anterior muco-buccal fold beneath the ala of the nose, most likely derived from remnants of the inferior portion of the nasolacrimal duct.
410	Koilionychia	The spoon shaped nails seen often in cases of severe anemia.
411	Koplik’s spot	The oral manifestation of measles that develop in the early course of the disease occurring as multiple ares of mucosal eerythema within which are areas of numerous small bluish white macule. These represent focal areas of necrosis.
412	Kveim test	It is a skin test for sarcoidosis where a sterile suspension of human sarcoid tissue is injected intradermally and a paponodular lesion develop at the site with in 4 to 6 weeks in cases of positive individuals.
413	Langerhans cell histiocytosis	See histicytosis X.
414	Lateral	Situated at the side.
415	Lateral periodontal cyst	A rare, slow-growing, non-expansile developmental odontogenic cyst derived from one or more rests of the dental lamina, containing an embryonic lining of 1 to 3 Cuboidal cells and distinctive focal thickenings or plaques.
416	LE cell	A cell that is a characteristic of lupus erythematosus and other autoimmune diseases. It is a mature neutrophil that has phagocytized a spherical inclusion derived from another neutrophil.
417	Leiomyoma	Benign neoplasm of smooth muscles. In oral cavity they arise from the vascular smooth muscle.
418	Leiomyosarcoma	Are malignant neoplasm of smooth muscles.
419	Lentigo maligna melanoma	Slowly evolving melanoma that develops within a pre-existing pigmented lesion on the sun-exposed skin of elderly patients.
420	Lepra cell	In histopathology of a lepromatous leprosy lesion, sheets of lymphocytes intermixed with vacuolated histiocytes called leprae cells.
421	Leser- trelat sign	The sudden appearance of numerous seborrheic keratoses with pruritis associated with an internal malignancy is known as the Leser- trelat sign.
422	Lesion	A site of structural in body tissues that is produced by disease or injury.
423	Letterer- Siwe disease	An acute disseminated disease with prominent cutaneous, visceral and bone marrow involvement of Langerhans cell disease primarily occurring in infants.
424	Leukemia	Represents several types of malignancies of haematopoietic stem cell derivation.
425	Leukocytosis	A temporary increase in the number of white blood cells circulating in blood.
426	Leukodema	A common, bilateral developmental anomaly of buccal mucosa of unknown cause characterized by a diffuse grayish white opalescent appearance of mucosa that disappears on stretching with a striking intracellular edema of the spinous cell layer.
427	Leukoplakia	Refers to greyishwhite, raised, unscrappable patch more than 5 millimeter in diameter which cannot be attributed to any other cause other than the use of tobacco, the definition carrying no histopathological connotation.  (Or) A predominantly white lesion of the oral mucosa that cannot be characterized as any other definable lesion; some leukoplakia will transform in to cancer. (Axell T, 1996)
428	Lichen planus	A common, bilateral, mucocutaneous disease where it presents as either white reticular, plaque, or erosive lesions with a prominent T lymphocyte response in the immediate underlying connective tissue. (Clinical; Histopathological)
429	Lichenoid eruptions	A common unilateral, mucocutaneous disease where it presents as either white reticular, plaque, or erosive lesions with a prominent T lymphocyte response in the immediate underlying connective tissue caused by an abnormal immunological reaction and clinically resembling lichen planus.
430	Linea Alba	A soft linear streak of hyper keratinized reactive tissue on the buccal mucosa along the occlusal line. The line may be formed by irritation from rough buccal cusps, bruxism or habitual clenching of teeth.
431	Linear gingival erythema	A thin narrow band of reddish along the free gingival margin commonly observed in HIV infected individuals.
432	Lingual mandibular salivary gland depression	See Stafne’s cyst.
433	Lingual thyroid nodule	A common developmental abnormality of tongue in which there is an accessory accumulation of thyroid tissue that is usually functional within the body of the posterior tongue.
434	Lingual varicosities	See Varicoses.
435	Lip pits	An autosomal dominant trait resulting in developmental defects of lip involving the paramedial portion of the vermilion of the lower and upper lip or the labial commissure area.
436	Lipid	Fat or fatty; a naturally occurring substance made up of fatty acids.
437	Lipid endoreticulotheliosis or Lipoid proteinosis	Are relatively rare group of inherited storage disorders resulting in lack of certain enzymes necessary for processing specific lipids resulting in accumulation of lipids within a variety of cells.
438	Lipoma	A benign neoplasm of normal fat cells that appears as a soft, movable swelling, often with a slight yellowish coloration.
439	Liposarcoma	A rare, malignant neoplasm composed of a wide spectrum of histologic patterns of the fat cells.
440	Lisch nodules	A translucent brown pigmented spots on iris seen in Neurofibroma.
441	Lobulated	Made up of lobules, which are smaller divisions of lobes as seen in brain, lung, and salivary glands. Some pathologic lesions are described as lobulated when the lesion is divided into smaller parts.
442	Local	Confined to a limited part, not general or systemic.
443	Ludwig angina	Is a cellulitis involving submandibular, sublingual and submental spaces leading to difficulty in breathing.
444	Lues	See syphilis.
445	Lues maligna	In the presence of compromised immune system, secondary syphilis exhibits an explosive and widespread form of syphilis with formation of necrotic ulcer.
446	Luetic glossitis	Diffuse atrophy and loss of dorsal tongue papillae in a diffusely enlarged lobulated and irregularly shaped tongue observed in syphilis.
447	Lupus erythematosus	Is an immunologically mediated multisystemic disease often involving skin, kidney and cardiac complications.
448	Lupus vulgaris	Refers to the tuberculosis of skin.
449	Lyell’s disease	See TEN
450	Lymphadenopathy	An enlarged lymph node due to an infection or a disease process or a neoplastic process in the area drained by the lymph node.
451	Lymphangioma	A developmental anomaly of lymphatic vessels with a benign proliferation of lymphatic vessels that occurs as a focal superficial lesion within the oral cavity and as a massive diffuse lesion of the neck like cystic hygroma.
452	Lymphoblastic	Pertaining to a cell of the lymphocytic series
453	Lymphocyte.	A variety of leukocyte or white blood cell that is important to the immune response and that arises in the lymph nodes. Lymphocytes can be large or small, and are round, non-granular, and classified as either T- or B-lymphocytes
454	Lymphoepithelial cyst	A cyst with a lumen lined by a keratinizing stratified squamous epithelium and a capsule containing multiple normal lymphoid follicles and a dense accumulation of normal lymphocytes.
455	Lymphoid tissue	Tissue composed of lymphocytes supported by a meshwork of connective tissue.
456	Lymphoma	Is a malignant disease of lymphoid system.
457	Macrodontia	Large teeth as compared to normal.
458	Macroglossia	A developmental or acquired disorder where the tongue is larger than normal.
459	Macrognathia	Large jaws as compared to normal.
460	Macrophage	A large, mononuclear phagocyte derived from monocytes. Macrophages become mobile when stimulated by inflammation and interact with lymphocytes in an immune response.
461	Macrostomia	An increase in the width of the mouth, resulting from failure of union of the maxillary and mandibular processes, with extension of the oral orifice toward the ear.
462	Macule	A focal area of color change that is flat and does not protrude above the surface of the normal tissue e.g. Freckles.
463	Malaise	A symptom that describes a feeling of uneasiness, discomfort, or indisposition.
464	Malignant	A neoplastic growth that grows rapidly, and can readily metastasize.
465	Malignant ameloblastoma A type of ameloblastoma which has metastasized.
466	Malignant potential	Is the risk of cancer being present in a potentially malignant state, either at initial diagnosis or in future and expressed in percentages.
467	Mandibular lingual cortical defect	See Stafne cyst
468	Marble bone disease	See Osteopetrosis
469	Margination	A physiological phenomenon that occurs during the early phases of inflammation in which white blood cells tend to occupy the periphery of the blood vessels and adhere to endothelial cells that line the vessels.
470	Mastication	Chewing.
471	McCune-Albright syndrome	A syndrome characterized by polyostotic fibrous dysplasia of the skeletal system, cafe-au-lait spots, and endocrine dysfunction.
472	Median mandibular cyst	A rare, developmental fissural cyst of questionable origin in the anterior midline of mandible arising from epithelium entrapped within the mandible during its fusion in embryonic life.
473	Median rhomboid glossitis	See central papillary atrophy of tongue.
474	Meiosis	The two-step cellular division of the original germ cells, which reduces the chromosomes to haploid.
475	Melanoma	A common malignant neoplasm of melanocytes occurring on skin and mucosal surfaces that commonly have a radial and superficial initial growth period before it extends into the deeper underlying tissues and metastasizes.
476	Melanosis	Disorder of increased melanin pigmentation that develops without preceding inflammatory disease; condition characterized by abnormal deposits of melanin (especially in the skin).
477	Melanotic macules	A small, flat, brown areas of the mucosal surfaces caused by an increase in the production of melanin granules but not in the number of melanocytes due to physiologic or reactive cause.
478	Mesenchymal	The meshwork of embryonic connective tissue in the mesoderm that gives rise to the connective tissue of the body, blood vessels, and lymph vessels.
479	Mesial	Toward the midline.
480	Mesiodens	A supernumerary tooth between the maxillary central incisors.
481	Metaplasia	Is a reversible change in which one adult cell type is replaced by another type. Or One form of epithelial cell changing to another due to various causes. Example  Ciliated respiratory epithelium becoming stratified in case of smokers.
482	Metastasis	The spread of neoplastic cells to parts of the body remote from the primary tumor and the establishment of new tumors in those sites via blood, lymph, direct seeding.
483	Metastasize	To spread or travel from one part of the body to another.
484	Metastatic tumor	A tumor formed by cells that have been transported from the primary tumor to a site not connected to the primary tumor.
485	Microcyte	A red blood cell that is smaller than normal.
486	Microdontia	Teeth that is considerably smaller than normal.
487	Microglossia	Tongue that is considerably smaller than normal.
488	Microstomia	Jaws that is considerably smaller than normal.
489	Midline lethal granuloma	A rare pathological process that is characterized clinically by aggressive destruction of the midline structures of palate and nasal fossa. Has been now classified as a type of lymphoma.
490	Mikulicz’s disease	A bilateral painless swelling of the lacrimal and salivary glands with an intense lymphocytic infiltrate, with destruction of acini and ductal cells becoming hyperplastic.
491	Miller’s liquefaction foci	Are formed by focal coalescence and breakdown of few dentinal tubules in dental caries and liquefaction focus is an ovoid area of destruction  parallel to course of dentinal tubule filled with necrotic debris that increases by expansion. This expansion compresses and distorts the normal dentinal tubules.
492	Miller’s theory	See acidogenic theory
493	Mitosis	The way in which somatic cells divide so that the two daughter cells receive the same number of identical chromosomes. The process that is responsible for growth.
494	Mitotic figure	Dividing cells caught in the process of mitosis.
495	Mixed tumor	See pleomorphic adenoma
496	Molluscum bodies	In infection with a DNA pox group of virus, molluscum contagiosum, the central portion in lobule is filled with bloated keratinocytes that contain large, intranuclear, basophilic viral inclusion called molluscum bodies.
497	Molluscum contagiosum	A DNA pox virus induced epithelial hyperplasia that presents as numerous papules that contain basophilic inclusion bodies called molluscum bodies. The lesion is more common in children and immunocompromised.
498	Morsicatio buccarum and linguaraum	A common reactive lesion arising due to chronic chewing of buccal mucosa (buccarum) and lingual (linguarum) appearing as thick, irregular, shredded white patch often with zones of erythema or bleeding. May reflect a sharp teeth or a stressful condition.
499	Mucocele	Is a common salivary gland cyst resulting from rupture of a salivary gland duct and spillage of mucin in to adjacent tissues.
500	Mucoepidermoid carcinoma	A common salivary gland malignancy with a variable biological potential, is made up of mucous producing acinar cells, epidermoid cells and intermediate cells.