Metastatic Renal Cell Carcinoma Presenting as Rapid Onset Iron Deficiency Anemia

Abstract

Iron deficiency anemia is a common referral to GI practice. This is a case of rapid onset iron deficiency anemia found to be secondary to metastatic renal cell carcinoma. A 54 year old woman presented with 3 weeks of fatigue, muscle weakness, palpitations, and SOB to her PCP. She had no abdominal pain or gross GI bleed. Last colonoscopy 4 years ago showed chronic internal hemorrhoids. Labs showed hemoglobin decreased from 15.2 to 7.2 (MCV 86.2, MCH 26.2) in a span of 8 months. She was also found to be iron deficient (Fe 18 ug/dL, TIBC 352 ug/dL, iron % saturation 5, ferritin 27 ng/mL). A hematologist started IV iron and referred to GI. EGD found a 4-5cm firm, friable mass in the descending duodenum. Cold forceps biopsy revealed metastatic high grade clear cell carcinoma. Staging CT showed a large Left renal mass, wall thickening of the duodenum, multiple sub-centimeter pulmonary nodules, and two areas of enhancement in the pancreas. She was started on systemic therapy sunitinib and oral iron. Her anemia resolved after 2 cycles of sunitinib. Cytoreductive Left laparoscopic nephrectomy confirmed grade 4 clear cell carcinoma. Renal cell carcinoma (RCC) rarely presents as the classic triad of flank pain, hematuria, and palpable abdominal mass. Several case reports describe patients presenting with melena from a bleeding duodenal mass, found to be invasive renal cell cancer (1,2). However, there are also case reports of RCC with IDA, and no abnormalities found on endoscopic exam (3,4). The proposed mechanism is increased tumor cell storage of iron via an apoferritin-like substance (3). The inadequate transfer of stored iron to plasma transferrin likely accounts for the iron-deficiency anemia. In the presentation of rapid onset iron-deficiency anemia without gross GI bleed, aggressive endoscopic evaluation, and CT scan in cases of negative endoscopic workup, may be necessary to diagnose occult metastatic RCC.Figure: Bleeding duodenal mass.Figure: Sagittal CT view of advanced Left renal cell carcinoma.