Recurrence of renal cell carcinoma with local invasion of the splenic flexure

A 58-year-old man presented with altered bowel habit, per-rectal bleeding and unintentional weight loss. Upon further investigation, he was found to have a normocytic anaemia and iron deficiency (haemoglobin 79 g/L, mean cell volume 81 fL and serum iron 5 μmol/L). The patient had a prior history of left nephrectomy for renal cell carcinoma (RCC) 13 months earlier. A colonoscopy was performed, at which time the endoscopist was unable to progress the colonoscope beyond the splenic flexure but did not visualize a colonic lesion. The patient subsequently underwent computed tomography (CT) colonography, demonstrating a large, polypoid, splenic flexure mass (Fig. 1). Staging imaging, including CT brain, chest, abdomen and pelvis, demonstrated no evidence of metastatic disease. Preoperatively, it was suspected that this lesion represented a primary colonic tumour, but a recurrence of RCC was considered. Three years earlier, the patient was found to have a 4-cm left mid-pole exophytic lesion for which he underwent a left partial nephrectomy. Histology demonstrated a pT3aN0 renal clear cell carcinoma with extension to the edge of the capsular margin. Two years later, surveillance investigations (positron emission tomography, CT urogram and cystoscopy) demonstrated tumour recurrence in the remnant left kidney and metastatic disease in the bladder. He subsequently underwent a transurethral resection of the bladder metastasis, followed by a complete left radical nephrectomy and partial cystectomy. Histology of the nephrectomy specimen demonstrated multiple foci of renal clear cell carcinoma, with tumour present in the renal vein margin. He did not receive any adjuvant chemotherapy or immunotherapy. The patient underwent a subtotal colectomy with end ileostomy formation. Intraoperatively, he was found to have a large colonic tumour at the splenic flexure with tumour invasion into the retroperitoneum and dilation of the proximal colon. This was excised en bloc, with histopathology demonstrating high-grade renal clear cell carcinoma (Fig. 2). RCC metastases involving the colon are rare with only several previous case reports. The most common sites of metastases for RCC include lung, lymph nodes, bone and liver. In a cadaveric study of 1451 patients with RCC, no solitary colonic metastases were identified. Intestinal involvement occurred in only 9% of patients (small bowel or colon was not specified), all of whom had multiple organ metastases. Local recurrence of RCC following radical nephrectomy occurs most commonly in the setting of systemic metastatic disease, with isolated local recurrence occurring in <2% of cases. Most commonly, local recurrence is confined to the renal bed, ipsilateral adrenal gland and/or ipsilateral retroperitoneal lymph nodes, but rarely involves the colon. Given the positive renal vein margin on the nephrectomy specimen, this case almost certainly represents a local recurrence. Aggressive surgical resection of local recurrence of RCC can be curative in many patients, and is preferred to radiotherapy or systemic therapies. Itano et al. reported en bloc excision of local