Pelvic and muscular metastasis of a renal cell carcinoma: A case report.

We report a case of an uncommon site of metastasis of a renal cell carcinoma. The most common sites of renal cell carcinoma metastasis are the lung, lymph nodes, liver, bone and adrenal glands; skeletal muscle metastasis is a rare occurrence. We report the case of a 75-year-old female who underwent a laparoscopic left radical nephrectomy for a renal neoplasm in 2011. The histological examination revealed the presence of a renal cell carcinoma, Fuhrman grade 2, with extensive necrosis and phlogosis areas (TNM 2009 RCC pT2a). Ten months later, the patient noted an indolent swelling on the proximal third of the right thigh and underwent a ultrasonographic and CT evaluation, documenting the presence of a pathological, solid bulk in the front of the right iliac vessels and in the rectus femoris muscle. The fine needle biopsy revealed a metastasis of renal cell carcinoma. The patient underwent 4 cycles of sunitinib therapy, followed by 3 cycles of salvage therapy with sorafenib, which were well tolerated. This unpredictable behaviour of RCC suggests the need to perform a thorough follow-up of patients.