Melanocytic nevi with features of Spitz nevi and Clark's/dysplastic nevi ("Spark's" nevi).

BACKGROUND: Nevi with cytologic characteristics of Spitz nevus and architectural features of Clark's/dysplastic nevus are not well recognized in the literature.

METHODS: Twenty-seven nevi with characteristics of Spitz nevus and Clark's/dysplastic nevus are reviewed.

RESULTS: The patients' mean age was 33 years, and 17/27(63%) patients were female. Lesions were most frequent on the trunk and lower extremities. Histopathologically, these nevi were composed of large, monomorphous spindled and/or epithelioid melanocytes. Spindle cells were often oriented parallel to the epidermis, with fused rete and lamellar fibroplasias. Lateral extension of the junctional component was a feature of compound lesions. An average of 10 years of clinical follow up in 12 patients revealed no recurrence or metastasis.

CONCLUSIONS: Recognition of this type of nevus is important to avoid confusion with malignant melanoma.