A rare case of genital porokeratosis clinically misdiagnosed as lichen planus

Introduction/Objective Porokeratosis is a clonal disorder of keratinization characterized by atrophic patches surrounded by a histologically distinctive hyperkeratotic ridge-like border called the cornoid lamella. Porokeratosis occurring on the genital area is considered a rare entity and much more unusual when in isolated form Methods/Case Report This is a case of a 54-year old man who presented with a penile lesion that has been present for 10 years, unchanged, non-bleeding and non-pruritic. There was no history of genital ulcer or inguinal swelling, neither any history of sexual promiscuity. The patient has a history of basal cell carcinoma on the right nasal area managed with Mohs surgery and scalp actinic keratoses treated with liquid nitrogen. On examination, there was a solitary 6-mm red linear macule with collarette of white scale on the corona of the penis. There was no similar lesion seen on other body parts. His blood investigations, including venereal disease research laboratory test (VDRL) and HIV screening, were negative. The initial clinical diagnosis was lichen planus, and triamcinolone was administered for three months with minimal benefit. This failed steroid management prompted a shave biopsy Results (if a Case Study enter NA) Histologic sections showed a column of hyperkeratosis arising from the epidermis (cornoid lamella) with absent granular layer and dyskeratotic cells beneath the cornoid lamella, confirming the diagnosis of porokeratosis limited to the genitalia Conclusion Porokeratosis is considered a pre-malignant condition based on clonal proliferation, dyskeratotic cells, abnormal keratinocyte maturation and p53 overexpression. Malignant progression to Bowen’s disease and squamous cell carcinoma has been documented in 6.9 to 30% of cases.