Mel-5 is a murine IgG antibody against a 75-kd protein that may be tyrosine-related protein (TRP-1).7- 9 The antigen appears to be particularly expressed in association with stage III and IV melanosomes.8 Epidermal melanocytes and the epidermal component of nevi and of melanomas are readily stained.10,11 The stain may be performed on frozen sections, as well as paraffin-embedded tissue. Our staining protocol (Table 1) requires 75 minutes, thus allowing for a multistaged excision and repair in the same day. The technique is simple and requires little extra equipment other than the antibody and a detection kit. Melanocytes stained with Mel-5 appear as heterochromatic dendritic cells. Compared with other immunohistochemical stains, Mel-5 is superior for this purpose because it so reliably stains epidermal melanocytes and melanoma cells.10 We feel that the best indication for micrographic excision with Mel-5 is for lentigo maligna, because of the superior ability to visualize the tumor and the irregular melanocytes at the margin. In addition, Mel-5 is indicated for micrographic excision of invasive melanoma to allow narrower margins in functionally or cosmetically critical locations. It is important to note that Mel-5 may not reliably stain amelanotic melanoma, desmoplastic melanomas, or the dermal component of melanomas.10 In our practice, we start with a 5-mm margin around the visible margin of the tumor as seen under examination with a Wood light. We employ standard micrographic mapping techniques to orient and section the tissue. Finally, we stain our sections with Mel-5, and often with HE as well. We use a section of tumor from the center of the lesion as a positive control, and often take a small biopsy specimen from the skin from the contralateral body site to serve as a negative control.