A case of ulcerated necrobiosis lipoidica with a giant plaque

A 54-year-old woman came to our hospital because she had noticed a gradually enlarging cutaneous tumor on her scalp 4 years previously. The first medical examination showed a 19 x 16 mm, firm, dark-red tumor with a crust on the frontal region of the scalp. Her mother and a cousin had had similar skin lesions. Histopathological examination revealed encapsulated jigsaw puzzle-like islands of epithelial cells appearing from the dermis to the subcutis. These islands consisted of two types of tumor cell : one had small, dark-staining nuclei and was located at the periphery of the islands and the other had large, light-staining nuclei and was located in the center of the islands. At this point, we diagnosed this tumor as dermal cylindroma. Two months after the resection, a new cutaneous tumor appeared at another site of the frontal scalp. We confirmed that the histopathological findings were similar to those in the primary lesion. We suspect that this patient had a rare tumor : familiar multiple dermal cylindroma. We discussed the relationship between the responsible gene for dermal cylindroma, CYLD, and the etiology of the tumor.