NEVUS:A benign, exophytic, usually pigmented,congenital lesion of the skin or mucosacomposed of focal collections of roundedmelanocytes (nevus cells).• The term nevus commonly used for mole.• Nevi mostly occur on skin, occasionally occur on mucous membrane.• Its also called birthmark.
Classification:• Intradermal (mucosal)• Junctional• Compound• Macular form also called Blue nevus• Epithelioid or Spitz
INTRAMUCOSL NEVUS:• It is also known as INTRADERMAL nevus.
CLINICAL FEATURES:• The lesion grows slowly.• It is generally less then 1 cm in diameter.• Intradermal nevus occurs in young patients and is one of common skin lesions. On skin it is raised or flat. It is tan or dark brown. It will often contain more hair than surrounding normal skin.
• Intramucosal nevus occurs in oral cavity mostly on the Hard palate or Gingiva. Its an asymptomatic. Pigmented. Brown to black. Slighted elevated papule or flat macule.
HISTOPATHOLOGY:• It is characterized by nests, cords or sheets of nevus cell confined to connective tissue.• Cells of nevus may be epithelioid, lymphocyte like, spindle or multinucleated types.• Mitotic figures are usually absent.• One of features of nevus is presence of fibrous connective tissue zone which separates it from overlying epithelium.
TREATMENT:As a general rule all solitarypigmented papules or nodules ofthe oral cavity should be excised.Once excised nevi do not tend torecur.
CLINICAL FEATURES:• It is benign.• Brown to black lesion.• Occurs primarily on the skin and occasionally on oral mucosa.• Within oral cavity it usually appears as a pigmented macular lesion on the hard palate or gingiva.
HISTOPATHOLOGY:• It is characterized by the presence of nevus cell nests in the basilar region of epithelium.• No nevus cells found in surround connective tissue.• Careful examination is required because similar type of focal proliferation of melanocytes (junctional cavity) occurs in melanoma.• It is important to note it can transform to malignant melanoma.
TREATMENT:It should be excised and submitted tohistopathological examination. Onceexcised, a junctional nevus does nottend to recur.
• It has the combined characteristics of the intramucosal nevus and junctional nevus.• Exhibiting nevus cells in the basal region of the epithelium and the adjacent connective tissue.
CLINICAL FEATURES:• Compound nevus is far more common then other nevi.• In oral cavity it tends to occur as pigmented papule or macule.• It occurs on hard palate or gingiva.TREATMENT:The nevus is treated by anexcisional biopsy that serves as adiagnostic and therapeuticprocedure.
CLINICAL FEATURES:• The blue nevus in benign pigmented lesion that presents as a dark blue dome-shaped papule or as a flat macule on the skin or mucosa.• It occurs most commonly on the hard palate.
HISTOPATHOLOGY:• In blue nevus pigment-producing cells are spindled and fusiform dendritic cells.• Cells are confined to the connective tissue.• They are separated and parallel to the normal overlying epithelium.• Macrophages often present among dendritic cells.• They have no tendency to transform into malignant lesion.
TREATMENT:Excisional biopsy is performed,which is also serves as thedefinitive treatment for thislesion.
• It is also called Spitz nevus and formerly called a “benign juvenile melanoma.CLINICAL FEATURES:• It presents as a solitary small pink to reddish-brown papule.• It occurs on skin of face and extremities of children.
HISTOPATHOLOGY:• It is usually composed of spindle shaped and large epithelioid nevus cells with abundant cytoplasm.• It is relatively circumscribed nests located at or near dermal and epidermal interface.• It is multinucleated.• Its size is 5 to 6 mm in diameter.
TREATMENT: Conservative excision of the entirelesion is curative.