Giant congenital pigmented naevus with unusual presentation and early malignant transformation in a Nigerian infant: case report and review of the literature

Abstract

A six month-old female infant with a giant congenital pigmented naevus is reported because of the rarity and unusual presentation and early malignant transformation. It was the first case to be documented in our centre. There was an extensive giant, darkly pigmented naevus of the "bathing trunk" distribution noted at birth, associated with multiple darkly pigmented smaller naevi scattered over the trunk and limbs. Bv the third month of life large pigmented lesion began to demonstrate small papillomatous projections studding the entire surface and at age six months nodular and warty excrescences appeared including a large pedunculated spherical mass attached to the anal verge. The labia majora became anatomically disfigured by these nodular, warty lesions of various sizes associated with the large pigmented hairy naevus. Histological examination of the excised large perianal and vulvar nodules showed the typical picture of an intradermal naevus consistent with giant congenital pigmented (melanocytic) naevus. The deeper portions of the lesion showed features of malignant transformation. The rapidity of evolution of the lesions including histologic features of early malignant transformation and the gross disfiguring of the genitalia and perineum are uncommon presentation of this melanocytic naevus. In view of the early malignant transformation immediate surgical treatment was indicated. Unfortunately the patient was lost to follow-up. The case report is complimented with a review of the literature.