Subungual Invasive Squamous Cell Carcinoma with Doubtful Underlying Bone Invasion: A Treatment Proposal

<b><i>Introduction:</i></b> Subungual squamous cell carcinoma (sSCC) is the most frequent malignant tumor of the nail unit. When suspecting sSCC, accurate diagnosis is supported by nail biopsy. Depth of invasion and histopathologic signs of human papillomavirus (HPV) infection are related to an unfavorable prognosis. In this case, it is necessary to rule out bone invasion by radiography or MRI, and in case of doubt, amputation is indicated. <b><i>Case Presentation:</i></b> We present 2 cases of sSCC with a confirmatory biopsy of sSCC with HPV and invasion; in both cases, MRI was difficult to distinguish between bone invasion and bone marrow inflammation. Before amputating the distal phalanx, we decided to perform a bone biopsy during the excisional surgery. Neither case required amputation. <b><i>Conclusion:</i></b> We propose that when an invasive sSCC is present and an MRI is doubtful of bone invasion, before amputating, a bone biopsy should be performed.

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.