Perils of diagnosis and detection of subungual squamous cell carcinoma.

Subungual squamous cell carcinoma often presents with atypical clinical manifestations, which can lead to delays in diagnosis. The presence of a tumor can be masked by the presence of infections or other misleading pathological conditions. The authors report on techniques for adequate biopsy and excision of such tumors. A case of subungual squamous cell carcinoma with invasion into the underlying bone is presented. Clinical histopathological evidence is reviewed along with human papillomavirus typing. Accurate diagnosis requires a high index of suspicion and appropriate tissue sampling.