Melanoma frequency among symmetrical Spitzoid-looking lesions: A retrospective study

BACKGROUND: Many efforts have been spent attempting to define clinical, histopathological and molecular markers for differential diagnosis of Spitz nevus and melanoma. Dermoscopy has been widely used but it may be not always sufficient. METHODS: A retrospective study was performed evaluating Spitzoid-looking lesions showing symmetry at clinical and dermoscopic examination in patients ≥12 years attending our Clinic from 2004 to 2014. Demographic, clinical and dermoscopic data were assessed for each lesion in order to highlight the most common characteristics which could help the differential diagnosis between Spitz nevus and melanoma when clinical or dermoscopic asymmetry is lacking. RESULTS: A total of 760 lesions were excised. 690/760 (90.8%), were identified as typical Spitz nevi, whereas 70/760 lesions (9.2%) consisted of malignant melanocytic lesions. Our study showed that almost 9.2% of clinically and dermoscopically symmetric Spitzoid lesions revealed to be malignant melanocytic lesion. For symmetric Spitzoid looking lesions female sex, clinical palpability, the presence of an inverse network at dermoscopic examination and the involvement of lower limbs were observed as the main factors, which were linked to a higher possibility of being malignant lesions. CONCLUSIONS: In order to avoid missing diagnoses for malignant melanocytic lesions, this study remarked the importance of preventive excision for all Spitzoid-looking lesions in patients ≥12 years, even if they show symmetry at both clinical and dermoscopic level.