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SCC of nail unit often misdiagnosed, affects older middle-aged men

Squamous cell carcinoma of the nail unit primarily affected men aged in their 60s, with diagnosis often incorrect or delayed, according to study results.

Researchers in Belgium used a dermatopathology database to study the records of 51 patients (mean age, 60.8 years; 72.5% men) with 54 squamous cell carcinoma (SCC) tumors from 1995 to 2011 and recontacted the patients.

In 53 SCC tumors, the fingers — most commonly the right index and long fingers (20.8% each) — were affected. The nail bed was the most common location within the nail apparatus (57.4%), followed by the perifungal area (31.5%) and both nail bed and perifungal area (11.1%).

Subungual hyperkeratosis, onycholysis, oozing and nail plate destruction were the most common clinical signs. Sixty-three percent of the SCC of the nail unit (SCCnu) tumors were in situ. For all treatments, the mean recurrence rate was 30.6%.

The study’s retrospective design was cited by the researchers as a limitation.

Researchers said misdiagnoses of SCCnu include onychomycosis, viral warts, chronic paronychia, eczema, melanoma, subungual keratoacanthoma, subungual exostosis, posttraumatic dystrophy, fibrokeratoma, onychopapilloma or onychomatricoma.

“[SCCnu] mostly affects men aged 50 to 69 years old,” the researchers concluded. “Clinical features are various and illusive, most often leading to a misdiagnosis of a wart. … This misdiagnosis is the reason that multiple misguided treatments are often attempted before biopsy is performed.

“Conservative surgical resection should be the first-line treatment when the bone is not involved. Recurrence rate is high when a procedure other than Mohs micrographic surgery is performed.”