S6183 Pleomorphic Carcinoma of the Lung Presenting With Iron Deficiency Anemia Secondary to Small Bowel Metastasis

Introduction: Small bowel metastasis of pleomorphic lung carcinoma is a rare but clinically significant phenomenon, as pleomorphic lung cancers have a high propensity for early and widespread metastasis. Clinically, the patient may present with abdominal pain, obstruction, or gastrointestinal bleeding, though patients are usually asymptomatic and lesions are detected incidentally. We present a case of symptomatic anemia due to chronic blood loss caused by metastasis of primary lung cancer. Case Description/Methods: A 66-year-old African American man with recently diagnosed metastatic pleomorphic (sarcomatoid) pulmonary carcinoma on palliative chemotherapy presented with shortness of breath and hemoptysis. He denied overt gastrointestinal bleeding. Labs revealed acute on chronic iron deficiency anemia. Microcytic anemia had been present since 2018, at which time endoscopy was recommended though not pursued by the patient. A computed tomography scan of the abdomen and pelvis with intravenous contrast revealed numerous liver lesions consistent with known metastasis and an unremarkable stomach, small bowel, and colon. An esophagogastroduodenoscopy (EGD) and colonoscopy were scheduled; however, the patient did not tolerate bowel preparation in order for colonoscopy to be performed. The EGD revealed Los Angeles grade D reflux esophagitis, non-erosive gastritis, and a single duodenal bulb arteriovenous malformation (AVM) that was treated with argon plasma coagulation. The next day, he underwent a small bowel enteroscopy due to the clinical risk of having a simultaneous distal small bowel AVM that showed several cratered jejunal ulcers with friable mucosa and irregular borders. Biopsies from the jejunal ulcers showed metastatic, poorly-differentiated carcinoma, consistent with lung primary. Due to the patient’s poor performance status and aggressive malignancy that does not respond well to systemic treatment, the patient decided to proceed with hospice care and subsequently expired. Discussion: In conclusion, our case highlights the importance of small bowel evaluation in the setting of iron deficiency anemia and primary lung carcinoma. In metastatic lung cancer, small bowel metastasis is a recognized though uncommon cause of occult or overt bleeding and standard endoscopic evaluation may miss these lesions.