Life-threatening onychomycosis imitator.

Although onychomycosis is one of the most common dermatological conditions, the exact diagnosis should be carefully confirmed, especially in therapy-resistant cases. Considering the potential for development of various nail disorders that could resemble the clinical picture of typical onychomycosis, the performing of a diagnostic biopsy is sometimes of paramount importance, in order to exclude the possibility of a life threatening onychomycosis imitators. Here, we present a case of subungual malignant melanoma, diagnosed by histological examination in a patient who had received long term, ineffective treatment for onychomycosis.