BH10 Subungual tumours, a multicentre retrospective study over 30 years

Abstract

Subungual tumours are rare compared with other skin sites. Early diagnosis of malignant conditions like melanoma and squamous cell carcinoma (SCC) is crucial. Causes of late presentation include lack of patient or doctor awareness; misdiagnosis as onychomycosis, haematomas or infections; slow growth and patient’s denial; nonspecific symptoms and amelanotic melanoma. Specialist clinical assessment, dermoscopy, adequately sized biopsies and skilled dermatopathologists are essential for diagnosis. We aimed to analyse the age and sex distribution, site, type and subtype and tumour stage in a retrospective series. A free-text search was carried out of ‘nail’ histopathology reports from 1995 to 2025 at two hospital sites. Infections, haematomas, melanocyte activation, naevi and dermatosis were excluded. In total 107 tumours were found. The patients’ age range was 13–90 years (mean 49). The male-to-female ratio was 0.84 : 1. Regarding the side, 47 were on the right and 49 on the left (11 unknown). Biopsy types were incision, shave, punch, curettage, excision and amputation. Histopathology included melanomas (2 in situ, 13 invasive); SCC (12 in situ, 5 invasive); glomus (16); exostosis (22); fibroma, angiofibroma, fibrokeratoma, fibroepithelial polyp or onychopapilloma (n = 18); fibromyxoma, angiomyxoma or myxoid cyst (n = 8); enchondroma or osteochondroma (n = 3); neuroma (n = 3); cavernous haemangioma or Masson tumour (n = 2); poroma (n = 1); pilomatrixoma (n = 1) and angiolipoma (n = 1). The range of melanoma Breslow depth was 2.5–10 mm and the melanoma stage ranged from pT3b to pT4b. The melanoma site was mostly the big toe (n = 7); rare subtypes included spindle cell (n = 3) and amelanotic (n = 2). Being concealed beneath the nail plate and due to their rarity, subungual tumours may be missed or misdiagnosed, leading to delayed treatment and worse outcomes. The mean patient age was 49 years. Patients with melanoma presented late and most cases were located on the hallux (known to be the most common digit affected). SCC presented in fairly early stages. All other tumours were benign. This series demonstrates the broad range of subungual pathology and highlights the severity of subungual melanomas. Improving patient and clinician awareness may help in enhancing clinical outcomes of malignant subungual tumours.