Pseudocyst of the scalp.

Pseudocyst of the scalp is described in the Japanese literature as a skin-colored cystic tumor localized on the forehead, whereas alopecic and aseptic nodules of the scalp are described in the French literature as asymptomatic nodules on the scalp that lack a pseudocyst-like architecture. The etiology of these diseases is unknown, but the lesions are likely due to follicular occlusion. Here, we report a case of pseudocyst of the scalp in a 72-year-old woman. The patient had a dome-shaped painless tumor on her scalp. Histologic examination showed a pseudocyst-like architecture with no true cystic wall. Here, we report a case of pseudocyst of the scalp and summarize the characteristic features of both pseudocyst of the scalp and alopecic and aseptic nodules of the scalp.