S6131 Metastatic Renal Cell Carcinoma to the Terminal Ileum Presenting as Isolated Iron Deficiency Anemia

Introduction: Renal cell carcinoma (RCC) accounts for 2%–3% of adult malignancies and is known for its unpredictable metastatic behavior. While common metastatic sites include the lungs, bones, liver, and brain, gastrointestinal (GI) involvement is rare. Small bowel metastases, particularly to the terminal ileum, are reported in fewer than 1% of RCC cases and typically present with overt gastrointestinal symptoms such as melena, hematochezia, or obstruction. We present a rare case of delayed terminal ileal RCC metastasis presenting solely as iron deficiency anemia and hematochezia. Case Description/Methods: A middle-aged man with Von Hippel-Lindau syndrome and prior clear cell RCC status post bilateral partial nephrectomy was referred for evaluation of transfusion-dependent iron deficiency anemia. He reported fatigue, hematochezia, and right lower quadrant swelling. Re-staging computed tomography abdomen/pelvis revealed a 5 cm polypoid mass in the terminal ileum. Colonoscopy showed a fungating, ulcerated, partially obstructing lesion 4–5 cm from the ileocecal valve with overlying clots, suggesting recent bleeding. Biopsies confirmed metastatic RCC. Due to ongoing anemia and concern for worsening obstruction from the enlarging mass, the case was reviewed by a multidisciplinary tumor board. Surgical resection was pursued for definitive bleeding control and to prevent future obstruction. Final pathology confirmed poorly differentiated RCC. Discussion: Terminal ileal metastasis from RCC is extremely rare, occurring in fewer than 1% of cases, and isolated presentation with iron deficiency anemia and hematochezia is highly uncommon. Such nonspecific symptoms can delay diagnosis. With improved imaging and prolonged survival in RCC patients, rare metastatic patterns such as small bowel involvement are increasingly recognized. This case underscores the need for ongoing clinical vigilance and endoscopic evaluation in patients with a remote RCC history and obscure GI bleeding. Surgical intervention may be warranted for both therapeutic and preventative purposes in select cases.