Dermoscopic-Pathologic Correlates of Invasiveness and Nevus Visibility in Nevus-Associated Melanoma

Nevus-associated melanoma (NAM) is histologically defined by coexisting nevus and melanoma components, yet the nevus component is frequently not visible on dermoscopy. We performed a retrospective, single-centre observational study including histologically diagnosed NAMs (2011-2024). Dermoscopic images were assessed independently by two readers. Histopathology was systematically revised to quantify nevus proportion, size, and depth. Univariate and multivariable logistic regression evaluated associations with (a) invasive vs. in situ NAM and (b) dermoscopically visible vs. non-visible nevus component. Among 340 NAMs, 36.8% were in situ and 63.2% invasive. A dermoscopic nevus was visible in 45.6%. In multivariable analysis, nevus visibility under dermoscopy was independently associated with histopathologic features such as larger nevus size, particularly 2.1-4 mm (OR 2.5, 95% CI 1.3-4.6), 4.1-10 mm (OR 3.7, 95% CI 2.0-7.0), and > 10 mm (OR 5.3, 95% CI 1.4-20.0), whereas deep nevus location (OR 0.3, 95% CI 0.2-0.5) and ulceration (OR 0.2, 95% CI 0.1-0.6) reduced visibility. Invasive NAM was independently associated with a visible nevus component under dermoscopy (OR 2.5, 95% CI 1.7-3.7), shiny white structures (OR 5.0, 95% CI 2.6-9.4), negative pigment network (OR 1.9, 95% CI 1.2-3.2), and blue-white veil (OR 8.3, 95% CI 4.5-15.4), whereas atypical pigment network and melanoma pigmentation were inversely associated with invasion. Dermoscopic nevus visibility in NAM is mainly determined by nevus size and depth, while melanoma-related changes, particularly ulceration, can obscure the nevus component. Dermoscopic markers of invasiveness should prompt timely management even when an associated nevus is suspected.