To the editor: The recent paper by Heinz Kutzner and co-authors introduces a new variant of superficial spreading melanoma composed predominantly of large hypercellular nests of melanocytes.1 The recognition of this particular pattern without a pagetoid element has been delayed as the histopathology masquerades as an unusual nevus. The clinical features, dermoscopy, the distinctive histopathology and now the application of comparative genomic hybridization, all help to identify this as a melanoma variant. Although the authors have linked this unusual nevoid melanoma to superficial spreading melanoma, this has necessitated a major change in the histopathological criteria traditionally applied to superficial spreading melanoma. There may be alternative distinctive pathways that need to be considered.

While exploring the relationship of atypical (dysplastic) nevi in the elderly to melanoma,2 the same experience emerged in the discrepancy between the clinical and dermoscopic findings that favoured a melanoma and the histopathological features which appeared nevoid. These melanocytic lesions when broad-based,often had criteria for defining transition to lentigo maligna3 or lentiginous melanoma.4 More recently, the results of FISH analysis have supported the existence of this controversial subtype of lentiginous melanoma5 that often evolves from atypical lentiginous nevi.

The atypical nevus of the elderly is an unstable nevus, and one variation which I have also observed2 is the hypercellular nested variant described by the authors. I have reported these as in situ nevoid melanomas. The cellular morphology is usually associated with crowded small to medium hyperchromatic melanocytes. The progression of these atypical nested melanomas is often to a small cell (nevoid) melanoma, which may become desmoplastic.

Although from a clinical perspective the term superficial spreading melanoma is appropriate for this nested melanoma, at least some of these tumors may be linked to an aberrant nevus pathway seen in elderly individuals explaining their unusual pattern that resembles a bizarre nevus.

The authors have clearly defined and have highlighted a potentially important variant of melanoma that will now be recognized more frequently. The eventual classification of this melanoma needs further work in reference to the unstable atypical nevi seen in elderly individuals that may evolve as melanomas including this predominantly nested non lentiginous pathway.