Giant microcystic adnexal carcinoma of the scalp

Microcystic adnexal carcinoma (MAC) is an uncommon, locally aggressive tumor. It typically involves the upper lip of middle-aged adults, and in rare instances the scalp. We report a Japanese woman with a giant MAC on the scalp. Physical examination revealed a 110 mm x 120 mm induration on her parietal region. Microscopically, the tumor showed both pilar and sweat gland differentiation. Resection included the cranium; for reconstruction we used a titan mesh allograft and covered it with a free latissimus dorsi muscle flap and a mesh skin graft. Ours is the first case of a MAC measuring more than 100 cm2 arising on the scalp of an individual in the third decade of life.