Metastatic Basal Cell Carcinoma: A Biological Continuum of Basal Cell Carcinoma?
Panel 1: a nodulo-ulcerative basal cell carcinoma (BCC) plaque having characteristic indurated margins and pigmented crusts in the centre over back. Note the BCC lesion involving the margin of old linear scar. Panel 2: a large irregular nodulo-ulcerative fleshy plaque in left axilla. Puckering suggests adherence to other structures. Note typical beaded and pigmented borders and 3 morphologically similar lesions in its vicinity. Also note small satellite papulonodules indicative of local spread (arrow heads). Panel 3 (histology (A)): epidermis shows focal epidermal ulceration while dermis has numerous nests of basaloid cells (H and E, ×10). (B) The basaloid cells have increased mitotic activity and are arranged in peripheral palisading pattern with areas of central necrosis (H and E, ×40). (C and D) Tumor infiltrating the deeper layers is suggestive of infiltrative BCC (H and E, ×10 and ×40). Panel 4: CT scan (arrows) shows homogenously enhancing tumor infiltrating the underlying lymph nodes and muscles in right axilla (A) and left axilla (B). A subcutaneous tumor along the posterior axillary line (C). Enlarged lymph nodes in pretracheal region (D).