Abstract
Background: Diagnosis of nevoid melanoma (NeM) is often difficult because NeM closely resembles a common nevus clinically and histologically. Methods: A retrospective study was conducted on 110 patients diagnosed with and/or treated for primary nevoid melanoma at the Veneto Institute of Oncology and at the University Hospital of Padua from August 1999. Results: Mean Breslow thickness was of 1.4 mm. Sentinel lymph node biopsy was conducted in nearly half of the patients, and positivity was detected in 16.7% of them. Twenty-four clinical and 23 dermoscopic pictures were collected. Papular and macular lesions prevailed over nodular and plaque-type lesions. Different hues of brown, pink, and red color were most represented. Twenty nevus-like NeMs and four multicomponent-pattern NeMs were observed. The Most frequent dermoscopic patterns for nevus-like NeM were atypical pigmented reticulum, irregular globules and dots, and hyperpigmented blotches. Atypical vessels, asymmetric peripheric striae, blue-white veil, and areas of regression were less frequent and prevailed in multicomponent pattern NeM. A structureless pattern was also featured. Many patients in the series had multiple melanomas. However, none of them had numerous multiple nevoid melanomas. Conclusions: NeM should not be regarded as a separate biological entity from classical melanoma, and the same histological and clinical prognostic factors apply to NeM. Clinically and dermoscopically, it often resembles benign nevi, although some clues such as evolution and some dermoscopic patterns could suggest malignancy. Clinical suspicion might prove crucial to further pathological analysis and recognition.