Mantleoma is a benign neoplasm that arises from the infundibulum and is characterized by a complex pattern formed by mantle-like cords of immature and mature sebocytes.

Steffen was the first to recognize and depict a neoplasm of mantle epithelium, but he confused matters by using the same name, mantleoma, that Ackerman and co-workers (he among them) had employed earlier that same year for a hamartoma (fibrofolliculoma-trichodiscoma). An attempt to lessen the confusion introduced by Steffen was to refer to Steffen's "mantleoma" as "a benign neoplasm of the mantle," as was done in a monograph about "Neoplasms with Sebaceous Differentiation" by Steffen and Ackerman published in 1994.