Trichoblastic infundibular cyst.

We report 4 cases of an infundibular cyst that histopathologically showed small papillary projections of follicular germinative cells emanating from the basal layer of the cyst wall. Some of these projections branched and formed a reticulated pattern. This cystic lesion is histopathologically distinctive. We propose to designate it as a trichoblastic infundibular cyst because its lining resembles that of an infundibular cyst, yet it has cells that resemble those of the follicular germ in its wall.