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Case Reports

Abstract

Porokeratosis, precipitated by a clonal keratinization pathway abnormality and hallmark histopathological cornoid lamella, possesses many variants. Porokeratotic Acanthoma (PA) is a rarer one. Here, we present the case of a 93-year-old man who had a solitary hyperkeratotic lesion on his left anterior leg, gradually increasing in size. Physical exam revealed a 1cm hyperkeratotic erythematous plaque on the left anterior leg. A biopsy was performed to rule out a squamous cell carcinoma. The sections revealed vertical columns of parakeratosis in discrete foci, associated with marked verrucous epidermal hyperplasia and hyperkeratosis. Beneath this, the granular layer was also decreased, diagnostic features of Porokeratotic Acanthoma (PA), distinct from conventional porokeratosis in its multiple and dispersed cornoid lamellae. Notably, the same risk factors predisposing someone to development of porokeratosis do not necessarily predispose someone to developing PA. Malignant transformation has not yet been observed in a PA, whereas a premalignant association has been established in porokeratosis. Given the patient’s advanced age, the treatment strategy was to monitor the lesion through a regular routine full body skin exam every 6-12 months. Treatment for PA lacks long-term follow-up data, so it is treated similarly to porokeratosis. We report this novel case to increase documentation of Porokeratotic Acanthoma (PA) cases and allow for better understanding of its potential risk factors and treatment strategy, ultimately building a more robust clinical picture.