Connective tissue nevus masquerading as a localized linear epidermal nevus

A 22-year-old black female patient presented to the dermatology clinic with an eruption on her left arm. The eruption consisted of hyperpigmented grouped papules with a verrucous appearance. Because the lesions were soft on palpation, the eruption was diagnosed clinically as an atypical localized linear epidermal nevus. Examination of a biopsy specimen of the lesion, however, revealed marked fibroblastic proliferation and pronounced dermal fibrosis, along with epidermal changes of hyperkeratosis, focal hypergranulosis, and papillomatosis. These findings are consistent with connective tissue nevus with epidermal changes suggestive of epidermal nevus. Therefore a deep biopsy is strongly suggested to rule out the possibility of connective tissue nevus in suspected cases of atypical linear epidermal nevus.