Subungual Squamous Cell Carcinoma in a Patient with Psoriasis

Subungual squamous cell carcinoma (SCC) is a rare malignant tumour with an indolent course and unknown aetiology. It is usually misdiagnosed as a benign lesion, resulting in delayed treatment. Although psoriasis is not a precancerous skin condition, the treatment modalities cyclosporine and psoralen with ultraviolet A (PUVA) might increase the risk of developing cutaneous SCC, although a relationship has not been confirmed. We describe a patient with psoriasis who had been treated with cyclosporine and PUVA 6 years previously. He developed back SCC 2 years later, a subungual skin lesion after another 2 years and presented to us 1 year later, when nail elevation and biopsy revealed SCC.