SECTION EDITOR: MARY S. STONE, MD; ASSISTANT SECTION EDITORS: SOON BAHRAMI, MD; CARRIE ANN R. CUSACK, MD; MOLLY A. HINSHAW, MD; ARNI K. KRISTJANSSON, MD; LORI D. PROK, MD
Histologic evaluation revealed an endophytic cup-shaped invagination composed of multiple papillary projections and islands lined by a double layer of cuboidal to columnar cells that emanated from the surface epithelium into the dermis. The stroma of the papillary processes contained numerous plasma cells. Beneath this were numerous dilated ducts and tubules exhibiting decapitation secretion.
Syringocystadenoma papilliferum is an uncommon benign adnexal tumor that typically presents at birth or early childhood with a female predilection. The vast majority of lesions present on the head or neck, with up to 40% arising within a preexisting nevus sebaceus.1 Less common locations include the trunk, extremities, axilla, and genital region, with most of these arising de novo unassociated with a nevus sebaceus.2 Approximately 5% of SCAPs occur on the extremities, with 71% of those cases occurring on the thigh.1
Grouped Erythematous Papules and Nodules on the Thigh—Diagnosis. Arch Dermatol. 2012;148(12):1412. doi:10.1001/archderm.148.12.1412-c