Primary Cutaneous CD4-Positive Small/Medium Pleomorphic Lymphoproliferative Disorder in skin

Lessons From the Friday Unknowns

The patient is a healthy 6 year old boy who developed a persistent red papule on his left cheek 5 months ago.

Histologic sections show a dense, dermal lymphocytic infiltrate involves full-thickness of dermis, with focal extension into superficial subcutaneous tissue and with a narrow zone of relatively uninvolved superficial dermis (Grenz zone) present above the infiltrate and beneath the…