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Case Reports

Abstract

Pseudoepitheliomatous keratotic and micaceous balanitis (PKMB) is a rare type of HPV-independent penile lesion hypothesized to be associated with progression to verrucous carcinoma or usual-type keratinizing penile squamous cell carcinoma (PSCC). Few cases of PKMB have been described in the literature and its pathogenesis is not well understood. We present a case of a 77-year-old male with a past medical history of psoriasis, lichen sclerosus, and recurrent scrotal cellulitis treated with ceftriaxone now presenting with a grey plaque on his left medial penile shaft. A punch biopsy was performed and demonstrated acanthosis, exuberant spongiosis, pseudoepitheliomatous hyperplasia, confluent parakeratosis, and a band-like lymphocytic inflammatory infiltrate at the epidermal and dermal junction with basal vacuolization and dyskeratosis. The basal keratinocytes were atypical and demonstrated occasional basal mitotic figures. In the superficial dermis there was a lymphohistiocytic infiltrate with prominent eosinophils. Immunohistochemical and special stains were performed. PAS-H showed thickening of the basement membrane, and no fungal organisms were identified. The lesion was p53 wild type, p16 negative, and Ki67 highlighted the basal layer of the lesion. The clinical, morphologic, and immunohistochemical findings in this case were consistent with PKMB. Despite its rarity, the clinical and histopathologic overlap PKMB shares with benign inflammatory conditions and other malignant and pre-malignant entities makes it an important differential to consider when diagnosing and ultimately treating penile lesions.