Folliculotropic metastatic melanoma: a distinct variant of metastatic melanoma

To the Editor, Cutaneous metastases of melanoma usually present as nodules composed of atypical melanocytes in the dermis and/or subcutis. In certain conditions, metastatic melanoma may show epidermotropism. Epidermotropic metastatic melanoma represents a rare variant of melanoma that is characterized histopathologically by atypical melanocytes within the dermis and also within the overlying epidermis, and lateral extension of atypical melanocytes within the epidermis beyond the dermal component is usually not observed.1 Epidermotropic metastatic melanoma sometimes shows an exclusively intraepidermal pattern that can simulate melanoma in situ.2,3 Although epidermotropism is a well-recognized phenomenon in association with melanoma, folliculotropic metastasis has not yet been described. Herein, we report a case in which multiple metastases of melanoma showed folliculotropism. A 63-year-old Japanese male presented with a gradually enlarging pigmented lesion on his right neck. The resected specimen revealed nodular melanoma (pT3bN0M0, Stage IIB). After surgical removal, the patient remained free from recurrence or metastasis during 27 months of follow-up. The patient subsequently noticed two small black papules. One was 6 mm in diameter and was from the left thigh and the other was 3 mm in diameter and was from the right cheek. Histopathologically, these two papules represented intradermal metastases without associated epidermotropism or folliculotropism. Consequently, extensive dermatological examination revealed 20 small black papules, each 1–2 mm in diameter, involving the bilateral face, left shoulder, bilateral upper arms, left thorax and right thigh. All of these small papules were A