Patho Part 1 PDF - Dental Pathology

Here is the transcription of the image into a structured markdown format. ### Number **Anodontia:** * **Complete True Anodontia:** All teeth are missing. This very rarely occurs and is usually associated with hereditary ectodermal dysplasia. * **Partial Anodontia (Congenital Missing Teeth):**...

Here is the transcription of the image into a structured markdown format. ### Number **Anodontia:** * **Complete True Anodontia:** All teeth are missing. This very rarely occurs and is usually associated with hereditary ectodermal dysplasia. * **Partial Anodontia (Congenital Missing Teeth):** A congenital absence of one or more teeth. The permanent teeth usually affected are the third molars followed by the maxillary lateral incisors and the second premolars. * Congenially missing teeth are uncommon in the primary dentition. When occurring, it usually involve the maxillary lateral incisors. ### Number * **Oligodontia:** The absence of 6 or more teeth. * **Hypodontia:** The absence of few teeth (less than 6). * **Hyperdontia:** Development of an increased amount of teeth, the additional teeth are called supernumerary teeth. --- ### Number **Supernumerary teeth:** * Teeth in excess of the normal number. It occurs more common in the maxilla (90%) than in the mandible (10%). * A supernumerary tooth in the maxillary anterior incisor region is termed a *mesiodens*, an accessory fourth molar is often called a *distomolar* or *distodens*. A posterior supernumerary tooth situated lingually or buccally to a molar tooth is termed a *paramolar*. * Supernumerary teeth are divided into supplemental (normal size and shape) or rudimentary (abnormal shape and smaller size) types. ### Number **Mesiodens:** * Is the most common supernumerary teeth. * Found in the palatal midline between the two maxillary central incisors. Almost always posterior to the normal centrals (allowing the centrals to erupt normally). * Morphologically the tooth is smaller with a cone-shaped crown and a short root. * May be erupted, impacted or inverted. * The best time for removal of the mesiodens in the primary dentition, is just prior to the eruption of the permanent maxillary central incisors. @ 6 years Early mixed --- ### Number **Natal & Neonatal teeth:** * Natal teeth are teeth present in newborns. * Neonatal teeth are arising within the first 30 days of life. * Most of these teeth are prematurely erupted deciduous teeth around 90% (around 10% are supernumerary teeth). * Those prematurely erupted primary teeth should be preserved if possible. * If the teeth are mobile and at risk for aspiration, removal is indicated, or they are impacting breast-feeding severely. ### Size **Macrodontia:** * Unusually large tooth. * Affects isolated teeth in the jaw. * Associated with hyperdontia. * Can be due to a systemic disease, e.g., pituitary gigantism. **Microdontia:** * Unusually small tooth. * Associated with hypodontia. * Lateral incisor affected most frequently (peg shaped). * Can be due to a systemic disease, e.g.,pituitary dwarfism. --- ### Shape * Gemination * Fusion * Concrescence * Twinning * Dens-in-dente (invaginatus) * Dens evaginatus * Ankylosis * Hypercementosis * Dilaceration * Taurodontism * Ectopic enamel * Abrasion * Attrition * Erosion * Abfraction The image includes a diagram of the following: GEMINATION, TWINNING, FUSION, CONCRESCENCE, One Tooth, Two Teeth, Dentin Union, Cementum Union (two teeth), (two teeth), One Bud, One Bud, Two Buds, Two Buds. --- ### Shape **Gemination:** * A partial division of a single tooth bud, to form a bifid crown with one common root. * Commonly found in the incisor region of primary dentition. **Fusion:** * A fusion of two separate tooth buds. May involve the entire length of the tooth (enamel, dentin and cementum) or just the roots (dentin and cementum). * Common in the incisor region of primary dentition. ### Shape Gemination and Fusion cont.: * Clinically, gemination and fusion can look similar. Radiographically different. * The larger tooth should be counted as a single tooth. * In gemination, the patient has a larger tooth but a normal number of teeth overall. In fusion, the patient has a larger tooth, but one less tooth overall. --- ### Shape **Twinning:** (old term) * Is the complete division of a single tooth bud into two completely separate teeth. **Concrescence:** * The union of the roots of two or more teeth caused by confluence of their cementum surfaces. It's believed to be related to overcrowding or trauma. * Most commonly seen in maxillary 2nd and 3rd\,molars. ### Shape **Dens-in-dente (Dens invaginatus):** * Technically means "tooth within a tooth". * Due to invagination of the inner enamel epithelium during development. * Most frequently involves the maxillary lateral incisors. * A mild form is characterized by the presence of an invaginated lingual pit that extends into the tooth. In its most extreme form the deep invagination results in a bulbous expansion of the affected root. * The base of the pit or deep invagination is composed of a thin layer of enamel and dentin that is extremely vulnerable to carious destruction. As a result, most teeth with deep invaginations quickly develop pulpitis, pulpal necrosis, and inflammatory periapical disease. *Inverted tear drop radiolucency with opaque borders.* --- ### Shape **Dens evaginatus (central tubercle, tuberculated cusp, accessory tubercle):** * Results from the opposite mechanism of dens-in-dente. Here there is evagination of the inner enamel epithelium. * More common in premolar teeth. It occurs more in the mandible than maxilla. * The accessory cusp normally consists of enamel and dentin, with pulp present in about half of the cases. * Clinically it looks like an extra cusp on posterior teeth "cusp of Carabelli" and as a "talon" cusp on anterior teeth (maxillary lateral and central incisors). * Dens evaginatus is also seen in association with another variation of coronal anatomy called *shovel-shaped incisors*. Dens Invaginatus vs. Dens Evaginatus Comparison Diagram: The image has two diagrams. The Dens Invaginatus diagram shows an enamel pit extending into the tooth. It labels a lingual pit extension and the dental pulp. The Dens Evaginatus diagram shows a bulge extending outward from the tooth. It includes an accessory cusp and pulp extension. --- ### Shape **Ankylosis:** (some times dentine) * The fusion of cementum directly to the surrounding alveolar bone. * It is associated with hypodontia. * Ankylosis may be secondary to many factors like trauma, injury, chemical, thermal irritation, or genetics. * The most ankylosed tooth is the mandibular primary 1st molar followed by the mandibular primary second molar, the maxillary primary first molar and the maxillary primary second molar. * The ankylosed tooth is usually found in infraocclusion as the patient grows. * Percussion produces a sharp solid sound of the involved metalic tooth. ### Shape **Hypercementosis (Cemental Hyperplasia):** * Accumulation of secondary cementum that is usually confined to the apical half of the root. It is asymptomatic. * Usually affects vital mandibular molars and premolars. * Radiographically, it is a bulbous enlargement with a distinct unbroken periodontal membrane space and a normal lamina dura. * Many factors can cause hypercementosis, some of which include Paget's disease) hyperthyroidism, pituitary gigantism, supra-eruption, periodontal infection, and occlusal trauma. --- ### Shape **Dilaceration:** * An abnormal bend or curve of the root during its development. * It is thought to result from a traumatic episode, usually to the primary dentition. * Consistent finding in children with congenital ichthyosis. * Grossly deformed teeth require surgical removal. The extraction of affected teeth may be difficult and result in root fracture on removal. ### Shape **Taurodontism (Bull-like tooth):** * Characterized by a large and long pulp chamber with short roots, increased apico-occlusal height, bifurcation close to the apex and a lack of constriction at the cemento-enamel junction. * Affects permanent teeth more frequently than deciduous teeth. * Increased frequency of Taurodontism has been reported in patients with hypodontia, cleft lip, and cleft palate. * The unusual root shape probably results from late invagination of Hertwig's root sheath. * No treatment is required but can be a complicating factor during root canal treatment procedures. --- ### Shape **Ectopic enamel:** * Droplets of ectopic enamel, or so-called enamel pearls (enameloma), may occasionally be found on the roots of teeth. * It forms when cells of the Hertwig's epithelial root sheath do not migrate away from the dentin and differentiate into fully functional ameloblasts and deposit enamel. * Most commonly in the bifurcation or trifurcation of teeth but may appear on single-rooted premolar teeth as well. * Maxillary molars are more commonly affected than mandibular molars. * Radiographically, they appear as well-defined, radiopaque nodules along the root's surface. ### Shape **Ectopic enamel cont.:** * **Cervical enamel extensions (projections)** occur along the surface of dental roots; these extensions represent a dipping of the enamel from the cementoenamel junction toward the bifurcation of molar teeth. * Because connective tissue cannot attach to enamel, these extensions have been correlated positively with *localized loss* of periodontal attachment with furcation involvement. --- ### Shape **Abrasion:** Loss of tooth structure due to *non-masticatory* friction. An example includes tooth brushing which leaves a "V" shaped notch on the cervical margin of the canine/premolar area. Abrasive foods can also cause tooth abrasion. **Attrition:** Wearing of tooth structure due to normal or excessive *masticatory* functions (bruxism). Leaves polished "facets" on incisal and occlusal surfaces. **Erosion:** Loss of tooth structure due to *non-mechanical* means. For example bulimic individuals expose the tooth to stomach acids which erodes the enamel. **Abfraction:** When a piece of enamel near the cemento-enamel junction fractures off due to flexure of the tooth mastication. The image then shows examples with photos of all four examples written above. --- ### Structural * Amelogenesis Imperfecta * Enamel Hypoplasia * Dentinogenesis Imperfecta * Dentin Dysplasia * Regional Odontodysplasia ### Structural **Amelogenesis Imperfecta:** * An inherited ectodermal disorders that represents a defect in enamel formation (pulp, dentin and cementum are normal). * Normal enamel formation progresses through three stages: 1. Enamel matrix formation. 2. Mineralization of the enamel matrix (primary mineralization). 3. Enamel maturation (secondary mineralization). * Most cases of amelogenesis imperfecta fall into one of three clinical types: *hypoplastic, hypocalcification* or *hypomaturation*. * Many subtypes of the three major groups are recognized; these are based on different inheritance patterns, clinical appearances, and radiographic features. * Several genes that are involved in enamel formation (amelogenin, enamelin, kallikrein 4, MMP20, others) are mutated in various forms of this condition. --- ### Structural **Amelogenesis Imperfecta cont.:** * Three main types include: **Hypoplastic (Type 1):** * Most common form. Defect in the ***amount*** of enamel present. However, it is well mineralized and does not chip. * Deficiency in enamel matrix due to lack of differentiation of the cells of the inner enamel epithelium to ameloblasts. * Enamel thickness thinner than normal in focal or generalized areas. ### Structural **Amelogenesis Imperfecta cont.:** * The crown size varies from small to normal and the teeth may lack interproximal contacts. * Enamel thickness and colour (from normal to opaque white-yellow-brown) varies. * Radiographically, enamel looks normal (its radiopacity is greater than the adjacent dentin). --- ### Structural **Amelogenesis Imperfecta cont.:** **Hypomaturation (Type II):** * Quantitatively there is normal thickness of enamel however the matrix is ***immature (containing residual enamel protein)***, so the enamel chips and abrades easily. * Teeth vary from creamy opaque colours to yellow/brown (dentin underneath the enamel). The surface of the tooth is soft and rough. * Dental sensitivity. * Radiographically, the enamel has *similar* radiopacity as dentin. ### Structural **Amelogenesis Imperfecta cont.:** **Hypocalcified (Type III):** * The quantity of the enamel is normal. However, the matrix is ***poorly calcified (lack of enamel proteins).*** * Enamel chips and abrades easily. * It has the similar characteristics as the hypomature type of Amelogenesis Imperfecta clinically. * Radiographically — the enamel is ***less*** radiopaque than dentin. --- ### Structural **Amelogenesis Imperfecta cont.:** * In general, both the hypomaturation and the hypocalcifications variants demonstrate defects in mineralization. * In reality, the distinction is hazy with a spectrum of enamel quality encountered. For this reason, many investigators prefer the term ***hypomineralization*** for both variants. * Treatment focuses on esthetics and protection of tooth tissue. * Restorative dental procedures at an early age not only preserve teeth but have a significant effect on the patient's self-esteem. ### Structural **Enamel Hypoplasia:**  * Same characteristics as the hypoplastic type of amelogenesis imperfecta however, it is more localized (one or a few teeth). * The causative factors are not genetic but environmental. * Defects may be small pits or affect the entire tooth. * Both deciduous and permanent teeth are affected. * Clinical signs include the lack of contacts, the rapid breakdown of the occlusal surfaces, and a yellowish-brown stain that appears when the tooth is worn down to dentin. --- ### Structural **Enamel Hypoplasia cont.:** * **Turner's hypoplasia:** Affects the individual's permanent teeth. It is caused by a **local infection** or trauma to the primary precursor. * The enamel defects vary from focal areas of white, yellow, or brown discoloration to extensive hypoplasia, which can involve the entire crown. * Most common in the permanent bicuspids because of their relationship to the overlying deciduous molars. *NOTE: Turner syndrome, a condition that affects only females, results when one of the X chromosomes is missing. Problems includes short height, failure of the ovaries to develop and heart defects. Micrognathia and high arched palate are common.* ### Structural **Dental Fluorosis:** * The ingestion of excess amounts of fluoride also can result in significant enamel defects known as *dental fluorosis* which leads to the formation of hypomineralized enamel that alters light reflection and creates the appearance of white, chalky areas. * Mild to moderate fluorosis ranges clinically from white enamel spots to *(mottled)* brown-and-white discolorations. * Severe fluorosis appears as pitted, irregular, and discolored enamel. --- ### Structural **Dental Fluorosis:** * The severity of dental fluorosis is dose dependent, with greater ingestion of fluoride during critical periods of tooth development causing more severe fluorosis. * Water fluoridation typically aims for a concentration between 0.7 to 1.2 ppm. In warm climates, the recommended concentration is 0.7 ppm due to higher consumption of water, whereas regions with more temperate climates use a concentration of 1 ppm. * The crowns of the maxillary central incisors are the most cosmetically important and demonstrate completion of their development by age 3. Therefore, close monitoring of all sources of fluoride intake during the first 3 years of life is recommended strongly. ### Structural **Syphilitic Hypoplasia:** * Congenital syphilis results in a pattern of enamel hypoplasia. * Anterior teeth altered by syphilis are termed **Hutchinson incisors** and exhibit crowns that are shaped like straight-edge screwdrivers. * Altered posterior teeth are termed **mulberry molars** and demonstrate constricted occlusal tables with a disorganized surface anatomy that resembles the bumpy surface of a mulberry. --- ### Structural **Dentinogenesis Imperfecta (hereditary opalescent dentin):** * An autosomal dominant condition in which abnormal dentin development occurs in both the primary and permanent dentition. * Even though the enamel is structurally normal, it fractures easily due to the fragile dentin supporting it. Root fractures are also common. * The teeth exhibit an unusual *translucent* or *opalescent* appearance with the colours varying from yellow-brown to grey. * Dentinogenesis imperfecta has been divided into three types. * Microscopically, the dentin of teeth in Dentinogenesis imperfecta contains *fewer*, but *larger* and *irregular*, dentinal tubules. ### Structural **Dentinogenesis Imperfecta cont.:** * The crowns have an excessive constriction at the CEJ which gives them a "bell or tulip" shape. * There are three types: **Type 1 (Shield I):** * Occurs in conjunction with osteogenesis imperfecta. Therefore, the patient will have a history of bone fractures and a *blue sclera*. * Teeth have obliterated pulp chambers, a bulbous crown, short roots and an opalescent amber color. * Primary teeth are affected more than permanent. --- ### Structural **Dentinogenesis Imperfecta cont.:** **Type 2 (Shield Type II):** * Most common form. Similar characteristics to Type 1 however it is not related to osteogenesis imperfecta. * Both primary and permanent teeth are affected equally. **Type 3 (Shield III-Brandywine Type):** * Features of type III that are not seen in type I and II include multiple pulp exposures, periapical radiolucencies, and teeth shell-like appearance. * Dentin appears thin, and the pulp chambers and root canal are extremely large, giving the appearance of thin dentin shells. ### Structural **Dentin Dysplasia:** * An autosomal dominant disease of the dentin that is unrelated to dentinogenesis imperfecta or any systemic diseases. There are two distinct types. * Affects both primary and permanent dentition. **Type 1 (Radicular Dysplasia):** * Most common type. * Affects both the primary and permanent dentition. Both dentitions are of normal color. * Clinically, the crown looks normal in colour and shape however, the teeth have increased mobility. * Abnormalities are directed towards the root of the tooth with extremely short roots, obliterated pulp chambers (with fragment of pulp called "chevrons") and periapical radiolucencies. --- ### Structural **Dentin Dysplasia cont.:** **Type II (Coronal Dysplasia):** * Colour of primary teeth is opalescent while permanent teeth are normal. * Deciduous teeth are similar in appearance to type 1 Dentinogenesis Imperfecta on radiographs. * Permanent teeth have enlarged pulp chambers that have a "thistle tube" appearance radiographically. * Permanent teeth pulp is filled with globules of abnormal dentin (pulp stones). * There are NO periapical radiolucencies. ### Structural **Regional Odontodysplasia:** * A localized non-hereditary abnormality that has an adverse effect on the formation of dentin, enamel and pulp (ALL structures). * Thin, poorly mineralized teeth radiographically look like "ghost teeth". * Affects teeth in a region or quadrant (more common in the Maxillary anterior region) in both primary and permanent teeth (more common in the permanent teeth). * Radiographically, the teeth have an extremely thin layer of enamel and dentin that surrounds an enlarged pulp chamber. * Short roots and open apices may be seen. --- ### Color * Abnormal colorations may be extrinsic or intrinsic. * Extrinsic stains occur from surface accumulation of an exogenous pigment and typically can be removed with a surface treatment. * Intrinsic stains arise from an endogenous material that is incorporated into the enamel or dentin and cannot be removed by prophylaxis with toothpaste or pumice. | Extrinsic | Intrinsic | | :----------------------- | :------------------------------- | | Bacterial stains | Amelogenesis imperfect (Al) | | Iron | Dentinogenesis imperfecta (DGI) | | Tobacco | Dental fluorosis | | Foods and beverages | Erythropoietic porphyria | | Gingival hemorrhage | Hyperbilirubinemia | | Restorative materials | Ochronosis Blue | | Medications | Trauma | | | Localized red blood cell breakdown | | | Medications | ### Color **Extrinsic stains:** * **Chromogenic bacteria:** green (most common) or black-brown to orange, most frequently in children, usually is seen initially on the labial surface of the maxillary anterior teeth in the gingival one-third. * **Tobacco products, tea, and coffee:** brown discoloration of the surface enamel, most frequently exhibit involvement of the lingual surface of the mandibular incisors. --- ### Color **Extrinsic stains cont.:** * **Medications:** stannous fluoride and chlorhexidine. * Fluoride staining may be associated with the use of 8% stannous fluoride and is thought to be secondary to the combination of the stannous (tin) ion with bacterial sulfides which will cause black stain. The labial surfaces of anterior teeth and the occlusal surfaces of posterior teeth are the most frequently affected. * Chlorhexidine is associated with a yellow-brown stain that predominantly involves the interproximal surfaces near the gingival margins. ### Color. **Intrinsic stains:** * **Hyperbilirubinemia**: yellow-green discoloration may accumulate in the developing teeth and become stained intrinsically. In most cases the deciduous teeth are affected as a result of hyperbilirubinemia during the neonatal period. * Most patients exhibit involvement limited to the primary dentition. Occasionally, the cusps of the permanent first molars may be affected. Causes of hyperbilirubinemia includes: Erythroblastosis fetalis, ABO incompatibility, premature birth and internal hemorrhage. --- ### Color **Intrinsic stains cont.:** * **Trauma:** Coronal discoloration is a frequent finding especially in the deciduous dentition. Posttraumatic injuries may create pink, yellow, or dark-gray discoloration due to localized vascular damage. * **Calcific metamorphosis:** A yellow discoloration is indicative of pulpal obliteration. ### Color **Intrinsic stains cont.:** * **Medications:** The most common is tetracycline, with the affected teeth varying from bright yellow to dark brown and, in UV light, showing a bright yellow fluorescence. The drug can cross the placental barrier; therefore, administration should, if possible, be avoided during pregnancy and in children up to 8 years of age. --- ### Diagnostic & Descriptive Terminology The image shows a pictorial breakdown of the following lesions: * Macule: non-raised area altered in color less than 1cm * Patch: pigmented area larger than a macule * Erosion: denudation above the basal layer of epithelium * Ulcer: denudation below basal layer of epithelium * Fissure: a linear crack in the epidermis --- The image shows a pictorial breakdown of the following lesions: * Papule: elevated, solid lesion less than 1 cm wide. * Plaque: flat or raised area more than 1 cm in diameter. * Nodule: deep and raised mass less than 1 cm wide. * Vesicle: small less than 1 cm fluid-filled skin elevation. * Pustule: vesicle fluid with purulent exudate. Puss. * Bulla: large more than 1 cm fluid-filled mucocutaneous elevation. --- * Cyst: epithelial-lined cavity. * Tumor: deep and solid mass more than 1 cm wide. **Incisional biopsy:** * Is a diagnostic surgical procedure in which a sample or portion of a lesion is removed for histopathologic examination. * Indications of incisional biopsy: * Ulcerated lesions (non-healing) *  Malignancy is suspected. * Lesion is located in a risky or hazardous location. * Lesion demonstrates differing characteristics in different location. * Large lesions (larger than 1cm. --- **Excisional biopsy:** * Is the removal of the entire lesions and to include a 2 to 3mm perimeter of normal tissue around the lesion. * Indications of excisional biopsy: * When lesion is most likely benign. * Definitive treatment of the lesion biopsied. * Vascular lesions. * Pigmented lesions unless you suspect the condition. * Small lesions (less than 1 cm) malignancy. Stratum corneum (Keratinized layer), Stratum granulosum (granular layer), Stratum spinosum (prickle layer), Stratum basale (basal layer) --- Here is a conversion of features of keratinized and nonkeratinized epithelium in a table format. | | Keratinized Epithelium | Nonkeratinized Epithelium | | :------------------------------------------------------ | :------------------------------------------------------------------------------------------------ | :--------------------------------------------------------------------------------------------- | | **FEATURES** | **CELL LAYER** | **FEATURES** | | Cuboidal or columnar cells containing bundles of fibers | Basal | Cuboidal or columnar cells containing fibers and other cell sites of most cell divisions | | Ovoid cells containing conspicuous fiber bundles | Prickle | Ovoid cells containing dispersed filaments | | Flattened cells containing fiber granules | Granular | Slightly flattened cells containing many dispersed tonofilaments and glycogen | | Extremely flattened and dehydrated cells | Keratinized | Slightly flattened cells with dispersed filaments and glycogen; present, but nuclei persist | | | | | #### Structure of the Mucosa in Different Regions of the Oral Cavity | REGION | COVERING EPITHELIUM | LAMINA PROPRIA | SUB | | :--------------------------- | :------------------------------------------------------------------------------------------------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------------------------------------------------------------------- | | Lining Mucosa | | | | | Soft Palate | Thin, nonkeratinized stratified squamous epithelium; taste buds present | Thick with numerous short elastic; fibers forming; on elastic lamina; vascular with well-defined capillary network | Diffuse tissue containing numerous minor salivary glands | | Ventral surface of tongue | Thin, nonkeratinized, stratified squamous epithelium | Thin with short papillae and fiber; a few minor salivary glands; layer in; reticular layer relatively avascular | Thin tissue containing fat and vessels, where absent, tissue is bound to tissue surrounding tongue musculature | | Floor of mouth | Very thin, nonkeratinized stratified squamous epithelium | Short papillae.; some fibers; extensive with anastomosing | Loose fibrous connective tissue containing fat, minor salivary glands | | Alveolar mucosa | Thin, nonkeratinized stratified squamous epithelium | Connective tissue many elastic and elastic supplied by vessels. | Connective tissue containing; thick elastic fibers with periosteum of minor salivary glands | | Labial and buccal mucosa | Thick, nonkeratinized stratified squamous epithelium | Contains collagen and elastic vascular tissue with connective supply given off into papillae | Firmly attached connective elastin density with glands | | Lips: vermilion; intermediate zone | Short layer fat vermilion gland and gland in the in between the both. | #### Specialized and Masticatory Mucosa | REGION | COVERING EPITHELIUM | LAMINA PROPRIA | SUB | | :--------------------------- | :------------------------------------------------------------------------------------------------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------------------------------------------------------------------- | | Masticatory Mucosa | | | Gingiva| Thick, orthokeratinized or parakeratinized, stratified squamous epithelium often showing stippled surface| Long, narrow papillae; dense collagenous connective tissue; supply with anastomoses| Distinct layers aresa firmly attached and | Hard plate| Thick, of the plate are supplied and supplied ||Thick, mucosa firmly attached by collagen. --- A pattern of pigmented dots is shown covering a dark gray background. ### Pigmented Lesions * Melanoplakia (Physiologic Pigmentation) * Smoker's Melanosis * Melanotic macule * Nevus (moles) * Peutz-jeghers syndrome * McCune-Albright syndrome * Addison's Disease * Amalgam Tattoo * Heavy Metal Ingestion * Drug Induced Pigmentation * B-K mole syndrome --- **Pigmented Lesions** * Melanocytes (melanin-producing cell) have their embryologic origin in the neural crest. Those cells migrate to epithelial surfaces and reside among basal cells. They have multiple dendritic processes that extend to adjacent keratinocytes. * When melanocytes are active in pigment production or proliferation, they may be responsible for several different lesions in the oral mucosa, ranging from physiologic pigmentation to malignant melanoma. * A relative of the melanocyte, the nevus cell, which is responsible for pigmented nevi. They originate from cells that migrate from the neural crest to the epithelium and dermis (submucosa), or result from altered resident melanocytes. --- ### Pigmented Lesions **Melanoplakia (Physiologic Pigmentation):** * Generalized, symmetrical and persistent pigmentation of the oral mucosa that is usually found in darker skinned people. * It is not pathological at all, and it is due to increased melanin production not due to increased numbers of melanocytes. * Usually observed as a ribbon of darkness on the attached mucosa, but can be seen in other locations as well. * Histologically, melanin is found within surrounding basal keratinocytes. * Treatment is not necessary. ### Pigmented Lesions **Smoker's Melanosis:** * A benign abnormal production of melanin that is stimulated by the chemicals in tobacco smoke (polycyclic amines like nicotine and benzpyrene). * Not associated with an increase in melanoma or carcinoma. * Appears as pigmented areas, usually located on the anterior labial gingiva. Can be also found on the commissural and buccal mucosa in case of pipe smoking. * Histologically, there is increased melanin pigmentation of the basal cell layer of the epithelium. * Treatment: cessation of smoking. Improvement is expected over the course of months to a few years. Biopsy should be considered in case of unusual clinical changes like surface irregularity or increased melanin density. --- ### Pigmented Lesions **Melanotic Macule (focal melanosis):** * Most common melanotic lesions. * A brownish flat oral discoloration that is caused by a focal increase in melanin deposit. It appears as solitary (sometimes multiple), well-demarcated, uniformly tan to dark-brown, asymptomatic, round or oval macule with a diameter of 7 mm or less. * The vermilion zone of the lower lip is the most common site followed by buccal mucosa and palate. * Independent of sun exposure unlike freckles. ### Pigmented Lesions **Melanotic Macule (focal melanosis) cont.:** * Histologically, it is characterized by an increase in melanin in the basal and parabasal layers of an otherwise normal stratified squamous epithelium. * It is a benign lesion with no malignant transformation potential. * Treatment is not necessary, just for esthetics. A biopsy may be required to establish a definitive diagnosis of this lesion in case of recent onset, large size, irregular pigmentation, unknown duration, or recent enlargement. old --- ### Pigmented Lesions **Nevus (Moles):** * A flat or sometimes raised dark growth that is due to an increase in melanocytes or nevus cells. Usually less than 1 cm in diameter. * Nevus are common on the skin but less common in the intraoral region. When present intraorally they are usually found on the hard palate, but can be also seen on the gingiva and lips. * There are congenital (higher chance of malignant transformation) and acquired nevi (much more common). * Approximately 2% to 3% of large congenital nevi transform into malignant melanoma. ### Pigmented Lesions **Nevus (Moles) cont.:** diagrams included within descriptions --- Junctional nevus, compound nevus, intramucosal nevus image diagram is presented. ### Pigmented Lesions **Nevus (Moles) cont.:** * Acquired moles occur later in life and appear as dark slightly raised papules. In general they are uniform in color (brown, black, blue). * Benign nevus are classified into 5 types: * **Intramucosal nevus:** Most common type intraorally. Nevus cells are located in the connective tissue only (lamina propria) of the oral mucosa. The lesion is slightly raised, brown and less than 8 mm. * **Blue Nevus:** Second most common intraoral nevus. The dark blue color is due to the nevus cells inhabiting the deep connective tissue. * **Compound Nevus:** Rare intraorally. Nevus cells are located in both the epithelium and the connective tissue. --- ### Pigmented Lesions *Rare intraorally. Found at the interface of the epidermis and lamina propria.* \\ **Intradermal Nevus:** *Most common lesion of the skin. Nevus lie only in the dermis.* * The risk of malignant transformation of an individual acquired melanocytic nevus into cutaneous melanoma is low (approximately one Iin 3,000 to 10,000). * Current evidence does not suggest that oral inelanocytic nevi are a marker of increased risk for developing oral mucosal melanoma. * If a pigmented lesion shows ulceration, an increase in size and a darkening in color a biopsy should be performed. These changes inay indicate transforn ation into a malignant itelariorria ### Pigmented Lesions **Peutz-Jeghers syndrome (Hereditary Intestinal Polyposis Syndrome):** * Autosomal dominant genetic disease characterized by multiple pigmented macules and gastrointestinal polyps. * Intraoral/perioral macules are seen first before pigmentation on other regions. The lower lips are affected the most but can develop on the buccal mucosa, gingiva and hard palate. --- ### Pigmented Lesions Peutz-Jeghers syndrome cont.: * The intestinal polyps are usually found in the small intestine (jejunum and ileum) but can affect any region of the GI tract. * Signs of polyps include stomach pains, rectal bleeding and diarrhea. * There is increased incidence of cancer affecting the gastrointestinal tract (adenocarcinoma), ovary, breast, and male and female reproductive tract. * Patients should be monitored for tumor formation and should be referred for genetic diagnosis and follow-up. ### Pigmented Lesions **McCune-Albright Syndrome:** * Genetic disorder that encompasses: * A severe form of polyostotic fibrous dysplasia. * Brown patches called cafe-