Acquired Nevus of Ito: A Case Report and Review of the Literature

Background Acquired dermal melanocytosis (ADM) usually affects the face, most often as acquired bilateral nevus of Ota-like macules (ABNOM). Extrafacial cases are rare and remain poorly characterized.Objective To report a rare case of acquired nevus of Ito on the neck and review the literature on extrafacial ADM.Methods We conducted a comprehensive search of PubMed and Google Scholar from 1977 onward to identify all reported cases of extrafacial ADM. Clinical and histopathological features were extracted and analyzed.Results Seventy-four cases were identified, including our patient. Lesions predominantly involved the back, upper extremities, and sacral region. Only three cases, including ours, involved the neck. Histopathology consistently showed dendritic melanocytes in the dermis, with many cases staining positive for S100, HMB-45, and MART-1.Conclusion Extrafacial ADM is an uncommon variant with overlapping histologic and pathophysiologic features to facial forms. This report expands the limited literature and highlights the importance of considering ADM in the differential diagnosis of new-onset dermal pigmentation on the neck and other non-facial sites.