We discuss salient clinical and pathologic features of blue nevi, with emphasis on the most diagnostically challenging aspects involving recognition of some rare variants and differential diagnosis between atypical blue nevus and malignant blue nevus.
These features have to be distinguished from tumor necrosis, which can lead to diagnostic confusion with malignant blue nevus.
The term atypical cellular blue nevus has been applied to rare CBNs that show atypical histologic features and raise histologic differential diagnosis of malignant blue nevus.
Atypical mitotic activity and tumor necrosis have emerged as the features most specific for malignant blue nevus.
Key histologic features helpful in differentiating between cellular blue nevus, atypical cellular blue nevus, malignant blue nevus, and PEM are summarized in the Table.
Malignant blue nevus (MBN) is a rare form of aggressive melanoma first described by Allen and Spitz.
Malignant blue nevus usually has biphasic architecture similar to that of CBN.
Malignant blue nevus : report of four new cases and review of the literature.
Artur Zembowicz, MD, PhD, and Pushkar Phadke, MD, PhD, review clinical and histologic features of blue nevus, cellular blue nevus, and malignant blue nevus
, emphasizing recently described variants and critical differential diagnoses.