Acral Melanoma in an Irish Population: Clinicopathological Features, Molecular Profile and Implications for Early...

Acral melanoma (AM) is a rare, biologically distinct melanoma subtype arising on the palms, soles, and nail apparatus that is frequently diagnosed late and carries a worse prognosis than non-acral cutaneous melanoma. Population-specific AM data remain limited outside North America and East Asia, and Ireland's comparatively homogeneous population has not previously been described. We performed a retrospective, bi-institutional cohort study of 41 AM patients treated at two Dublin tertiary referral centres (2017-2023), using data from prospectively maintained melanoma databases, medical records, and pathology reports. Patients were predominantly older adults (median age 73, range 39-88) with a long delay before presentation: 80.5% reported an enlarging lesion for six months or more before seeking care. Lesions were predominantly located on the foot (73.2%), and acral lentiginous melanoma was the predominant histological subtype (82.9%). Median Breslow Thickness was 3.0 mm, and 75.6% presented with T stage ≥ 3. Amputation was required in 65.9% of patients to achieve adequate margins, 47.4% of those assessed had confirmed nodal disease, and 36.6% developed recurrence. Mutation testing, performed in a subset of tumours, identified BRAF, NRAS, and KIT alterations in a minority of cases, with a substantial proportion classified as triple-wild-type. Despite Ireland's unique germline background reported in cutaneous melanoma, this Irish cohort's mutational profile and advanced stage at presentation were broadly consistent with international cohorts. Earlier clinical recognition, standardised nail-unit biopsy technique, and a national melanoma registry could improve outcomes for this rare, high-risk subtype.