Clear cell papulosis: Report and review

Abstract

A 12-month-old boy presented with three months of asymptomatic hypopigmented flat-topped papules on the suprapubic skin and lower abdomen. Emollients and topical steroids offered no improvement and the patient was referred to the dermatology department. Shave biopsy revealed a papillated epidermis with scattered solitary mononuclear clear cells at all levels of the epidermis and an overlying basket weave orthokeratosis. The cells were epithelioid with increased amphophilic cytoplasm. Immunohistochemical staining was positive for CK7, CEA, and CAM5.2 and negative for S100, CD1a, and Mart-1. These findings were consistent with clear cell papulosis. No treatment was recommended as these lesions were asymptomatic. However, yearly follow up was recommended given the resemblance of these cells to those of Paget disease. Review of the literature demonstrates a total of 31 biopsy confirmed cases with AE1, CEA, and EMA positivity and S100 negativity as the most consistent staining properties. A recent retrospective review of 19 cases documents long term follow-up of at least six years and up to 21 years. The results suggested a tendency toward self-resolution and an absence of malignant progression, supporting the benign nature of these lesions.