Case 35 Female, 50 years. Recent, variably pigmented skin papule, arising in previously stable macule, upper legShow diagnosis & comments
(Spitzoid) nodular melanoma
There is a resemblance to Spitz naevus, but a number of findings points to malignancy: compact architecture of dermal cell groups, also at the base; nuclear atypia in all levels; dermal mitotic activity; thinned and stretched epidermis.
Since Spitz naevus resembles melanoma more closely than other naevus types (Sophie Spitz originally considered them to be melanomas that, for some reason, did not manifest their malignant potential in children), it follows that melanomas not uncommonly resemble Spitz naevus. If the resemblance is striking, such melanomas are sometimes referred to as 'spitzoid melanomas'.
Since this resemblance is independent of other parameters that allow subtyping of melanoma, there are spitzoid superficial spreading melanomas, spitzoid nodular melanomas, etc.
The spitzoid appearance does not have a bearing on the melanoma in terms of clinical behaviour.