Pigmented basal cell carcinoma developing on the lower extremities--three cases masquerading as malignant melanoma.

Three cases of pigmented basal cell carcinoma were reported which needed to be differentiated from malignant melanoma based on their location and clinical features. Clinicopathologically, they were characterized by a large number of melanophages in the stroma, blockade melanocytes in the parenchyma, and phagocytosis of melanosomes in tumor cells as well as a large number of intraparenchymal melanophages. Two cases were characterized by the aggregation of melanophages in cystic spaces caused by stellate atrophy.