Complete regression of primary cutaneous malignant melanoma.

While partial spontaneous histopathological regression is a common finding in invasive primary melanoma, proven complete regression is rare, with only 33 cases having been documented. None of the patients in these reported cases had a biopsy specimen taken from the original lesion, which would unequivocally prove the diagnosis of complete regressing melanoma. Over 4 years, we saw a 62-year-old white man who refused treatment of a biopsy specimen-proved superficial spreading melanoma (Breslow thickness, 0.7 mm) that eventually regressed completely. A biopsy specimen confirmed complete histopathological regression. There was no clinical evidence of regional or distant metastases throughout the 4 years. To our knowledge, this is the first documented case of a biopsy specimen-proved primary melanoma completely regressing. We present sequential photographic documentation and review the literature about this phenomenon. While the prevalence of such an event is unknown, evidence is presented that it may be more common than previously thought.