Abstract
BAP1 tumor predisposition syndrome is a hereditary disorder that increases the risk of a variety of benign and malignant tumors. Some patients with BAP1 tumor predisposition syndrome develop cutaneous lesions including BAP-omas, cutaneous melanomas, and basal cell carcinoma. We report a case of 62-year-old female with BAP-1 tumor predisposition syndrome presenting with intradermal nevus with extensive neurotization and neurofibroma-like changes. The patients past medical history is notable for adenocarcinoma of pancreas, cutaneous basal cell carcinomas and squamous cell carcinomas. On examination there were two firm, pink and dome shaped papules in the lower leg and multiple scattered benign appearing melanocytic macules and papules. Incisional biopsy of a papule from the right calf was performed. Histological examination revealed nests of intradermal nevus with extensive neurotization and neurofibroma-like changes. There are nests of benign nevus in the dermis with abundant spindled cells with wavy nuclei and neurofibroma-like changes. The nevoid melanocytes are positive for SOX-10, tyrosinase and p16; whereas negative for HMB-45. The neurofibroma like areas are positive for SOX-10 and p16, but negative for tyrosinase and HMB-45. Scattered mast cells (CD117 and mast cell tryptase positive) are noted within the neurofibroma-like areas but not in the nests of nevoid melanocytes. BAP-1 immunohistochemical stain revealed preserved nuclear expression of BAP-1 protein in the nevoid melanocytes and in the neurofibroma-like areas. Results of molecular studies including BRAF mutational analysis and TSO500 gene panel will be presented and discussed at the meeting. To our knowledge, intradermal nevus with extensive neurotization/ neurofibroma-like changes are very rare and have not been described in association with BAP1 tumor predisposition syndrome.
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