Case 25 Female, 22 years. Skin of lower legShow diagnosis & comments
Spitzoid SAMPUS (superficial atypical melanocytic proliferation of uncertain significance)
This lesion which is almost entirely intraepidermal, shows massive pagetoid spread of spitzoid melanocytes throughout its width. There are associated clusters of Kamino bodies.
Some regard such lesions as variants of Spitz naevus (pagetoid Spitz naevus); others feel that such massive ascent of enlarged melanocytes is indicative of in situ melanoma or microinvasive melanoma (depending on the presence of an intradermal component). Follow-up data are unlikely to provide a solution, since complete excision would lead to eradication of such a lesion in any case. This is wat makes the situation different from STUMP (Spitz tumour of uncertain malignant potential): a verdict of STUMP would mean that the lesion is not very superficial and therefore, if it is a melanoma, there is some chance of metastatic spread. In case of SAMPUS, there is uncertainty about the biology of the lesion but since it is also very thin, it can safely be assumed that complete excision will guarantiee that the lesion is eradicated.
If margins would be involved or threatened, a re-excision should certainly be advised.
- Busam KJ, Barnhill RL. Pagetoid Spitz nevus. Intraepidermal Spitz tumor with prominent pagetoid spread. Am J Surg Pathol. 1995 Sep;19(9):1061-7.
- Elder DE, Xu X. The approach to the patient with a difficult melanocytic lesion. Pathology. 2004; 36: 428-34.