Cancer Center of Boston at Plymouth, Framingham, MA, USA.
A case of spontaneous regression of pleural and intrapulmonary metastases from renal cell cancer is reported with more than 60 cases reported since the original review of this clinical phenomenon in 1964. The metastatic disease sites are most often pulmonary, but extrapulmonary sites include liver, bone, and CNS regressions. The role of nephrectomy in "spontaneous regression" continues to be obscure, accounting for < 50% of documented cases. Immunologic mechanisms, although intellectually attractive, have not been identified.