Authors
Huiru Wang, Peng Wang, Yanyan Suo, Kang Lu, Qingfeng Xue, Huahua Li, Rui Gao, Yunchang Guo, Songjia Qu, Xiaowei Cai
Published in
Frontiers in medicine. Volume 13. Pages 1991898. Epub Oct 09, 2026.
Abstract
Amelanotic subungual melanoma (ASM) is a rare variant of nail unit melanoma (NUM) lacking melanin pigmentation, frequently misdiagnosed as a benign post-traumatic or infectious lesion. To our knowledge, ASM becoming clinically apparent within 24 h following minor blunt trauma has not been reported previously. We report the case of a 66-year-old male who presented with a persistent flesh-colored nodule beneath his right thumbnail that was manifested within 24 h after minor blunt trauma caused by nail clippers. The lesion was non-tender, non-pigmented, and unresponsive to 2 weeks of antibiotic therapy. Histopathology revealed diffuse subepidermal proliferation of atypical cells with signet-ring morphology. Immunohistochemistry (IHC) demonstrated positivity for vimentin, HMB45, and Melan-A, and negativity for cytokeratin 5 (CK5) and S-100. Ki-67 was approximately 30%; Breslow thickness was 2.5 mm. Final diagnosis: ASM, AJCC stage IIA (T3aN0M0). Diagnostic excisional biopsy with a 2-mm margin was performed; sentinel lymph node biopsy of two axillary lymph nodes was negative. At 1-year follow-up, no local recurrence or distant metastasis was observed. This case demonstrates that ASM can become clinically evident within 24 h after acute trauma, likely through unmasking of a pre-existing subclinical tumor. For post-traumatic nail lesions unresponsive to antibiotics, early biopsy with a comprehensive IHC panel (including Melan-A, HMB45, and S-100) is essential.
PMID:
42920588
Bibliographic data and abstract were imported from PubMed on 24 Oct 2026.
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