Eczema‐Like Amelanotic Melanoma: A Diagnostic Challenge

Abstract

Amelanotic melanoma (AM) is a rare and aggressive variant of cutaneous melanoma characterised by the absence of pigmentation, often leading to delayed diagnosis due to its ability to mimic benign inflammatory or neoplastic conditions. We report the case of a 68‐year‐old woman presenting with a slowly enlarging, erythematous, mildly scaling patch on the left arm, previously misdiagnosed and treated as eczema and mycosis for 3 years without improvement. Dermoscopy revealed few non‐specific polymorphic vessels, while line‐field confocal optical coherence tomography (LC‐OCT) demonstrated hyperkeratosis and atypical dark cells throughout the epidermis with dermal invasion. Histopathological examination confirmed amelanotic melanoma (Breslow thickness 1.1 mm, Clark level IV, pT2a). Wide local excision and sentinel lymph node biopsy were performed, with no evidence of metastasis. This case highlights the diagnostic challenge posed by eczema‐like AM and underscores the importance of maintaining a high index of suspicion and performing biopsy in persistent, treatment‐resistant erythematous lesions.