C0666 - A Rare Case of Iron Deficiency Anemia Due to Lung Cancer Metastasis to Small Bowel

Andrew Mims, MD, Vick DiCarlo, MD, Steven Kessler, DO
The University of Tennessee Health Science Center, Chattanooga, TN

Introduction: Lung cancer remains the leading cause of cancer related death in the United States, likely due to its high malignant potential. While the brain, bone, liver, and adrenal glands are common sites of metastasis for lung cancer, metastasis to the GI tract remains rare. Here we present a rare case of primary lung cancer with symptomatic metastasis to the small bowel.

Case Description/Methods: A 48 year old M was referred to the Gastroenterology clinic for iron deficiency anemia and abdominal pain. A year prior, he was diagnosed with CK7 positive poorly differentiated Adenocarcinoma of the lung after a biopsy from a right upper lobe pleural mass. He underwent local radiation and chemotherapy with Carboplatin and Pemetrexed, followed by immunotherapy with Durvalumab. Follow up imaging in the interim showed excellent response to therapy.

A month prior to presenting to the GI clinic, he developed recurrent mid abdominal pain associated with food intake. Labs revealed iron deficiency anemia with Hemoglobin 5.2 g/dL, MCV 64.5 um³, Iron 9 mcg/dL. He denied overt GI bleeding. EGD and colonoscopy were negative for malignancy, however video capsule endoscopy showed areas of mucosal ulceration throughout the middle of the exam. Small bowel enteroscopy redemonstrated mucosal changes in the jejunum. Pathology from jejunal biopsies identified CK7 positive carcinoma, consistent with lung metastases to the small bowel. Follow up PET scan disclosed diffusely metastatic disease. Unfortunately, no treatment options remained, and patient died shortly thereafter.

Discussion: Symptomatic disease spread to the small bowel in lung cancer has been estimated to be 1.8%,¹ however autopsy studies have indicated rates of up to 11.9%². This discrepancy is likely due to minimal symptom burden associated with small bowel metastases. In addition, small bowel metastasis is often an extremely late presentation of disease, as nearly all patients with small bowel metastasis are found to have additional sites of metastasis³, thus lending to an extremely poor prognosis. This case was particularly interesting in that this patient’s only indications for metastatic disease were iron deficiency anemia abdominal pain due to small bowel metastasis. A high index of suspicion is needed for patients with a history of lung cancer who develop abdominal pain or iron deficiency anemia for the detection of metastasis.


Disclosures:


Andrew Mims, MD, Vick DiCarlo, MD, Steven Kessler, DO. C0666 - A Rare Case of Iron Deficiency Anemia Due to Lung Cancer Metastasis to Small Bowel, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.