Abstract

A 17-year-old female presented to an outside hospital with a pink pedunculated nodule on her mid lower back, that was initially diagnosed as herpes, although no treatment was attempted. Eventually, the patient presented to our institution with concern that the lesion was progressively increasing in size. It was associated with intermittent pruritus and bleeding when itched. Examination revealed a 1.7 cm mamillated fleshy pink nodule with focal crust and an inferior 2 mm pink papule on her mid lower back. The lesion was excised by saucerization biopsy technique and submitted to pathology for histopathological correlation. Microscopically, the lesion revealed well-circumscribed cystic invaginations of the epidermis filled with prominent papillary projections lined by a double cell layer of luminal columnar cells and basal cuboidal cells. The stroma of the papillary projections contained abundant inflammatory cells, predominantly plasma cells. The epidermis showed papillomatosis and hyperkeratosis with adjacent dilated ectopic apocrine glands. A diagnosis of syringocystadenoma papilliferum (SCAP) was made. SCAP is a benign adnexal hamartomatous lesion. These are often solitary congenital lesions, and commonly arise from a nevus sebaceus. The truncal location is rare, given the usually sparse and poor development of ectopic apocrine glands in this location. These lesions tend to increase in size during adolescence due to pubertal hormone stimulation. The prognosis of this lesion is excellent, with no reported metastasis in the literature. We present this interesting case, that this differential should be considered in a truncal site, especially if considering infectious entities such as herpes.

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