Spontaneous regression of subcutaneous in-transit malignant melanoma deposits of the lower leg after treatment with the carbon dioxide laser.

Primary malignant melanoma (MM) is one of the few cancers that can show spontaneous regression, and although this is well described, the mechanisms behind this are unclear. Spontaneous regression of secondary metastatic deposits of melanoma is rare and there are only a handful of case reports supporting this phenomenon. We report a patient with in-transit MM metastatic disease of the leg, who underwent carbon dioxide (CO(2)) laser ablation, and subsequently developed remission of untreated deposits. We discuss the possible immunological mechanism for this phenomenon.