Meningothelial hamartoma associated with nevus sebaceus.

Meningothelial hamartoma is a rare lesion of ectopic meningothelial elements that usually presents on the scalp at birth or in early childhood. The characteristic spindle cells infiltrate through collagen and stain positively for epithelial membrane antigen and vimentin but are negative for CD31 and CD34. This distinguishes meningothelial hamartoma from vascular tumors. Nevus sebaceus is a fairly common lesion that has been associated with several different benign tumors, including trichoblastoma and syringocystadenoma papilliferum. We describe the case of a 17-month-old girl who presented with a meningothelial hamartoma in association with a nevus sebaceus. To the best of our knowledge, this is the second case reported.