[Three patients with a Spitz naevus that later turned out to be a melanoma].

A melanocytic lesion was removed from each of three patients: 2 men aged 37 and 65 and 1 woman aged 45. The preferred diagnosis was 'Spitz naevus'. Subsequently, all three developed regional (sub)cutaneous and/or lymph node metastases, indicating that the lesions were melanomas. The histopathological distinction between Spitz naevus and melanoma is often very difficult. Classical Spitz naevi can be diagnosed correctly only if the entire lesion is available for histological examination. Incompletely removed lesions should be re-excised for further examination. Some melanomas resemble Spitz naevi, but can be recognised on the basis of well-defined histological indicators of malignancy. Some melanocytic lesions, however, cannot be categorised with confidence as being either benign (Spitz naevus) or malignant (spitzoid melanoma). Thus, a group of lesions with inconclusive histology remains and has been designated as 'atypical Spitz tumour' or 'Spitz tumour of uncertain malignant potential'. Generally, such lesions are best treated as melanomas.