Association of subungual melanoma and subungual squamous cell carcinoma: A case series.

BACKGROUND: Subungual squamous cell carcinoma (SSCC) and subungual melanoma (SUM) are rare tumors. Several case reports of association of SSCC with SUM (SSCC-SUM) have been published.

OBJECTIVE: We sought to document the clinical, dermoscopic, and histologic features in a case series of SSCC-SUMs and describe their relative frequency compared with those of SSCC and SUM.

METHODS: All patients who underwent surgical exploration of the nail apparatus with a dermatopathologic examination from 2012 to 2015 were reviewed retrospectively to identify all cases of SSCC, SUM, and SSCC-SUM. For patients with SSCC-SUM, clinical characteristics were obtained from electronic medical records. All histologic specimens were reviewed by 3 dermatopathologists.

RESULTS: The medical records of 456 patients were reviewed. SSCC was diagnosed in 78 (17%), SUM was diagnosed in 63 (14%), and SSCC-SUM was diagnosed in 9. Patients with SSCC-SUM accounted for 11% of those with a diagnosis of SSCC (9 of 78) and 14% of those with a diagnosis of SUM (9 of 63).

LIMITATIONS: This was a single-institution retrospective study.

CONCLUSION: The association of SSCC and SUM is relatively frequent in patients with SUM and warrants further consideration to understand the underlying mechanisms involved.