Pigmented nevus divided between recipient and donor sites by intermediate skin grafting procedure: a study with fluorescence method (Falck & Hillarp).

Pigment freckles seen in donor and recipient sites at intermediate skin grafting were studied, chiefly by means of Falck & Hillarp's fluorescence method, with the following results. (1) An important role is played by the regenerative eccrine sweat ducts in the mechanism of recurrence of so-called "lentigines" after incomplete removal. (2) Junctional activity, not associated with the regeneration of epidermal appendages, can recommence in the epidermis of intradermal nevi. (3) B-type nevus cells once again actively produce melanin. (4) Specific fluorescence was observed corresponding to the melanin granules distributed in the manner of "nuclear caps" in keratinocytes around junctional activities. This latter finding may indicate that melanosomes which still contain DOPA are transferred from melanin-producing cells to keratinocytes.