Infiltrating Giant Congenital Cellular Blue Nevus Of Neck Presenting As Melanoma

Blue nevus is an uncommon pigmented lesion of dermal melanocytes. By convention, two well defined histologic variants, designated as "common" and "cellular", have been recognized. These lesions have attracted much attention due to its confusion with malignant melanoma. We present a case of a giant congenital cellular blue nevus of neck clinically presenting as malignant melanoma and infiltrating vessels and underlying muscles resulting in incomplete removal. It is important to differentiate this lesion from malignant blue nevus and malignant melanoma on the basis of presence or absence of severe nuclear pleomorphism, nucleoli, mitotic activity and necrosis. However, malignant transformation is known to occur in these lesions and the importance of careful follow up is mandatory. This case highlights the difficulty in diagnosing this lesion and emphasizes the need for long term follow up in view of its uncertain malignant potential.