LAUSR

To the Editor: It is true that many pathologists do not use the diagnostic term lentigo maligna (LM) but instead lump all subtypes together as melanoma in situ (MIS). This highlights the very crux of the problem. Because of this convention, surgical margin guidelines cannot be based on subtype. Fortunately, our research showed there is no significant difference in subclinical extension between the 2 entities as used in real-world community practice. Many of our 2335 lesions were[1 cm in diameter. This size is typical of noninvasive melanoma (NIM) at time of diagnosis. A study of 340 consecutive primary NIMs from 11 different practices reported 77% were [1 cm in diameter. Nehal’s own study of LM reported the average lesion size was 11.3 mm. Regardless,when our analysiswas restricted to lesions \1 cm in diameter, 1-cm margins were still needed. The evidence for 5-mm margins is indeed empirical. Despite this common gut feeling, evidence from Nehal’s studies confirm that wider margins are necessary. In her study of LM, the average excision margin was 8 mm. Only 92.4% of lesions cleared with a 9-mm margin. In her recent publication, MIS required an average surgical margin of 6.5 6 2.4 mm. These studies add to the preponderance of evidence supporting the use of 1-cm margins for LM and MIS, and occasionally wider margins on the head and neck. We agree that one size does not fit all when dealing with NIM. Special consideration must be given to those that have wide subclinical extension or invasive components, but how does one predict that? The rule of 10s states specialty site melanomas