Minimal deviation melanoma.

Minimal deviation melanoma is a recent concept of uncertain biologic significance. Minimally deviant melanocytes are not seen in metastases, suggesting they do not have the same biologic behavior as clearly malignant cells. Therefore, the Breslow and Clark prognostic criteria may not be applicable. Eight patients with MDM are presented. All were treated by scar re-excision and primary closure. Lesions ranged from 0.31 to 1.65 millimeters thick and four were Clark's level IV. Median follow-up study has been 19 months without evidence of local recurrence or distant metastasis. We concluded that MDM has a low likelihood for aggressive behavior in spite of tumor penetration which might suggest otherwise and that radical surgical therapy appears unnecessary.