Solid and Cystic Clear Cell Hidradenoma with Focal Intracystic Carcinoma in-Situ

摘要

A rare case of a nodulocystic hidradenoma with intracystic carcinoma in-situ occurring in the scalp of a 79-year-old man is reported. Case Report A 79-year-old male presents an asymptomatic cystic nodule on his scalp. The excisional biopsy specimen shows a demarcated dermal neoplasm with both solid and cystic components. The solid area demonstrates sheets and nests of clear polygonal epithelial cells with small uniformed nuclei. The nuclear chromatin is dark and condensed without discernable nucleoli. The similar clear cells are present at peripheral areas of cystic component. The large cystic areas show intracystic hemorrhage, proteinaceous material, and necrotic cellular debris. Focally, the cyst lining shows dysplastic squamoid cells projecting in the lumen in a papillary configuration. The dysplastic cells exhibit nuclear pleomorphism, large eosinophilic nucleoli, and mitotic figures. The coagulative necrosis is also noted in the intracystic papillary structures. There is no overt stromal invasion. The neoplasm has high proliferative index with 15% Ki67 positive cells as well as approximately 5% P53 positive cells. The neoplasm is immunoreactive to EMA, but non-reactive to P63, GCDFP-15, androgen receptor and HMB-45. We interpret the tumor as a cystic clear cell hidradenoma associated with focal intracystic carcinoma in-situ.