S3361 A Case of Metastatic Renal Cell Carcinoma to the Colon

Abstract

INTRODUCTION: Renal cell carcinoma (RCC) originates in the renal cortex and constitutes 80-85% of primary renal malignancies in adults. Treatment of this condition ranges from partial or complete nephrectomy for isolated renal masses to chemotherapy for disseminated disease. In cases of metastatic disease, common sites include the lungs, lymph nodes, bone, liver and brain. The Gastrointestinal (GI) tract remains an uncommon site of metastasis of this malignancy. We present a rare case of RCC with colonic metastasis. CASE DESCRIPTION/METHODS: A 76 year-old-male with a past medical history of metastatic RCC treated with left radial nephrectomy (6 years prior) and chemotherapy (with Nivolumab) who presented with dyspnea on exertion. He was noted to have iron deficiency anemia; hemoglobin 5.6g/dl, MCV 65.9 A decision was made to perform colonoscopy and EGD. EGD was notable for gastric varices (IGV-1) and mild gastritis. Colonoscopy revealed a single, ulcerated, flat lesion 40 cm from the entry site that was biopsied. Remaining colon was unremarkable. Pathology of the lesion confirmed metastatic RCC to the Colon. Patient, underwent liver ultrasound that showed no lesions, left upper quadrant ultrasound with splenic vein visualized likely secondary to occlusion). Chest x-ray showed no acute cardiopulmonary abnormality._ Hematology and oncology was consulted and a plan for possible re-treatment with Nivolumab was made. DISCUSSION: RCC has been documented to metastasize to uncommon sites such as the cervix, pancreas and skin. Metastasis to the colon is exceedingly rare. Treatment typically involves nephrectomy or chemotherapy and patients usually undergo different with long term surveillance (e.g. BUN, Creatinine levels , CT/MRI head, abdomen pelvis) for recurrent disease depending on the stage. We feel that our study is important because it demonstrates a rare case of of secondary GI malignancy that may not be on the differential of many physicians. Keeping this diagnosis in mind when approaching future cases will likely allow for more prompt diagnosis and treatment of this condition.Figure 1.: Endoscopic photograph of flat, ulcerated polyp that was biopsied and eventually found to be metastatic prostate cancer.Figure 2.: Endoscopic photograph of the same flat, ulcerated polyp that was biopsied and eventually found to be metastatic prostate cancer.