<|> Basal cell carcinoma -
Typically, basal cell carcinoma is a locally invasive, slow-growing tumor of middle-aged persons, commonly occurring in whites. It rarely metastasizes. It occurs exclusively on hairy skin.
Predisposing conditions : Prolonged exposure to strong sunlight like those living in Australia and New Zealand.
Common locations :
Face (90%), usually above a line from the lobe of the ear to the corner of the mouth.
General appearance :
1. The most common pattern is nodulo-ulcerative, in which a slow-growing nodule undergoes central ulceration with pearly, rolled margins.
2. The tumor enlarges in size by burrowing and by destroying the tissues locally like a rodent. Hence it is called "Rodent ulcer".
Microscopic features :
1. Proliferation of basaloid cells.
2. Patterns of solid mass, masses of pigmented cells, strands and nests of tumor cells in morphea pattern, keratotic changes, cystic change with sebaceous differentiation, adenoid pattern with apocrine and eccrine differentiation.
3. The commonest pattern is solid basal cell carcinoma in which the dermis contains irregular masses of basaloid cells with characteristic peripheral palisaded appearance of the nuclei.