Spontaneous regression of primary renal cell carcinoma following image-guided percutaneous biopsy.

Spontaneous regression of metastatic renal cell carcinoma (RCC) is a rare but well-described clinical phenomenon; spontaneous regression of nonmetastatic RCC has been reported far less frequently. We present three cases of primary RCC that regressed spontaneously following the image-guided biopsy that established their diagnosis. We briefly review the literature describing spontaneous regression of both primary and metastatic RCC and emphasize how knowledge of this phenomenon may be useful for abdominal imagers that perform renal biopsy or interpret postbiopsy follow-up studies.