Fig. 5

BAP1-inactivated nevus/melanocytoma. a BAP1-inactivated melanocytoma arising within a common acquired nevus. Nests of small melanocytes are present in the superficial aspect (common acquired nevus). Larger melanocytes with abundant cytoplasm are present deeper within the dermis. b BAP1 immunohistochemistry demonstrates nuclear BAP1 expression in the melanocytes of the common acquired nevus, but not the BAP1-inactivated melanocytoma. c BAP1-inactivated melanocytomas are characterized by epithelioid melanocytes with pale pink cytoplasm, well-defined cellular membranes and nuclear pleomorphism. Some nuclei are eccentrically located within melanocytes