Common Blue Nevus with Satellite Lesions Needs a Differential Diagnosis from Malignant Melanoma

Malignant blue nevus is rare, and a common blue nevus rarely needs a differential diagnosis from malignant melanoma. Although a melanocytic nevus with a satellite lesion is usually suggestive of a peripherally disseminating malignant melanoma, very few cases of blue nevus with satellite lesions have been reported thus far. To our knowledge, this is the seventh case of a blue nevus with satellitosis. Periappendageal and perivascular concentrations of the nevus cells were observed in the main papule as well as in the satellite lesions. These findings suggest that blue nevus cells could infiltrate along the perivascular area in the dermis and form multiple satellite lesions. Blue nevus should be considered as a differential diagnosis when a locally disseminating malignant melanoma is suspected.