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.