image: Clinical and histopathological findings of subungual amelanotic melanoma. (A) Partial distal onycholysis of the left thumbnail at the initial stage (arrow). (B) Pale-red erosive proliferative lesions beneath the nail plate (arrows), observed after debridement of the detached nail plate. (C) Partial distal nail-plate defect in the advanced stage, accompanied by nail dystrophy and disappearance of lunula in the involved site (arrows). (D) A skin biopsy sample revealing epidermal ulceration. A large number of atypical tumor cells infiltrated the epidermis and dermis with partial nesting arrangement, and no pigment was detected in tumor cells (hematoxylin-eosin, original magnification 50×).
Credit: HIGHER EDUCATION PRESS
A 74-year-old Chinese man presented with a one-year history of distal onycholysis (nail separation) of his left thumbnail. He had no family history of melanoma and no trauma to the digit. The lesion was initially misdiagnosed as onychomycosis at a nail salon, where he received repeated manicure treatments without improvement. When the detached nail plate was debrided, pale-red proliferative tissue with erosion was visible underneath. Biopsy of the nail bed revealed atypical melanocytes with marked cellular atypia in both epidermis and dermis; immunohistochemistry was positive for Melan-A, HMB45, and Prame, with a high Ki-67 index. The final diagnosis was subungual amelanotic melanoma.
No metastasis was found on imaging. The patient underwent wide local excision and sentinel lymph node biopsy (negative) and was staged as AJCC IIIC (T3bN1cM0). Adjuvant therapy with interferon α1b and toripalimab was initiated. At six months of follow-up, there was no local recurrence or distant metastasis.
Subungual melanoma is more common in Asian and African populations (10–25% of all melanomas) than in Caucasians (1–3%). It typically presents as pigmented streaks or masses, but the amelanotic variant lacks pigment, making it prone to misdiagnosis as fungal infection, warts, pyogenic granuloma, or squamous cell carcinoma. This case highlights that persistent, isolated onycholysis or non-pigmented lesions under the nail should prompt histopathological evaluation without delay.
The work titled “Subungual Amelanotic Melanoma with Onycholysis as the First Manifestation” was published on Skin (published on August 21, 2026).
Journal
Skin
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Subungual Amelanotic Melanoma with Onycholysis as the First Manifestation
Article Publication Date
21-Aug-2026