Abstract

Mantleomas are rare hamartomas with sebaceous mantle differentiation that were first described in 1993 by Steffen. They are poorly understood and have only been described in the literature twice in our review. Histologically, they are composed of cords of basaloid cells that emanate downwards from the junction of the follicular infundibulum and isthmus. In response to increasing androgen levels, they may develop increased complexity and have more of an interweaved, retiform pattern consisting of sebocytes and sebaceous ductal structures. Follicular cysts may derive from various locations along the pilosebaceous unit, the most common of which is the infundibular cyst. While sebaceous differentiation can be seen in steatocystoma, mantle differentiation is rare. We present a case of a 61-year-old male who presented with a white-yellow papule on his left cheek. Histopathologically, the lesion showed anastomosing mantle-like basaloid proliferations, arising from the wall of an infundibular cyst. BerEP, CK20, CK7, CD117, and CD8 (focal) immunohistochemical stains were positive in the basaloid proliferation. The histological findings and immunohistochemical staining pattern support a diagnosis of mantleoma arising from an infundibular cyst. We present this rare case to increase awareness of this entity and to add to the paucity of information that is currently available.

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