Detection of malignant melanoma in a giant congenital naevocytic naevus by positron emission tomography.

Abstract

T.M. and C.A. contributed equally to this work. Sir, Giant congenital naevocytic naevi are rare, occurring in fewer than one in 10 000 newborns. The lifelong risk for their malignant transformation is up to 12%,1 and therefore prophylactic removal of the involved area is indicated, if feasible and practical. Because the naevus cells are initially located in the upper dermis and subsequently descend into the deeper dermis along hair follicles later in life, extensive dermabrasion should be performed as early as possible.2 However, surgical removal may not always be applicable, and long‐term follow‐up may remain the only option for management.3 If textural alterations appear in a giant naevus they should be excised, but nonspecific changes rather than malignant transformation are frequently seen. We describe the use of fluorodeoxyglucose‐positron emission tomography (FDG‐PET) for detecting the intralesional development of malignant melanoma in a giant naevus. The possible value of FDG‐PET for monitoring patients with widespread naevocytic naevi is highlighted.