Nevus-Associated Melanomas

• Published in: American journal of clinical pathology Vol. 142; no. 4; pp. 485 - 491
• Main Authors: Shitara, Danielle, Nascimento, Mauricio M., Puig, Susana, Yamada, Sérgio, Enokihara, Milvia M. S. S., Michalany, Nilceo, Bagatin, Ediléia
• Format: Journal Article
• Language: English
• Published: 01-10-2014
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1309/AJCP4L5CJGKTJVDD

Abstract
Objectives:
The clinical significance of nevus-associated melanoma compared with de novo melanomas remains controversial. It has been suggested that nevus-associated melanomas have a higher Breslow thickness and therefore worse prognosis. Over a 10-year period, this study evaluated the incidence of nevus-associated melanoma and its prognostic significance related to clinicopathologic features.
Methods:
Cross-sectional study from 1995 through 2004 in a dermatopathology referral center. With available data, we evaluated sex, primary location, histologic subtype, Breslow thickness, Clark level, presence of ulceration, associated lesion, and histologic subtype of the associated lesion.
Results:
Of 135,653 pathologic records from skin biopsy specimens over a 10-year period, 1,190 melanoma records were selected. Nevus-associated melanomas corresponded to 390 (32.8%) melanomas, with thin melanomas having a nevus 1.52 times the association observed with thick melanomas (>1.01 mm; 95% confidence interval, 1.16–1.99; P < .001). Superficial spreading melanoma was the most frequent, while no lentigo maligna melanoma was associated with nevi. The median Breslow thickness of nevus-associated melanomas was lower than that of de novo melanomas.
Conclusions:
Nevus-associated melanomas, which represent one-third of the melanomas in southeast Brazil, are associated with intermittent sun exposure, superficial spreading melanomas, and lower Breslow thickness. This is one of the largest series describing nevus-associated melanomas in Latin America.