Iron Deficiency Anemia: An Unusual Presentation of a Common Lung Disease

Abstract

Purpose: A 68-year-old Caucasian male with a past medical history significant for hypertension was recently diagnosed with stage IV large cell lung cancer in his left lower lobe with metastasis to the brain, liver and spine. At presentation, he was on Cisplatin/Pemetrexed and Cisplatin/Docetaxel. Routine blood work revealed Hb of 9 mg/dl, MCV of 82, Iron of 36, saturation of 14% and a Ferritin of 218; consistent with iron deficiency anemia. Patient was referred to our gastroenterology service for endoscopic workup of his anemia. Upper endoscopy revealed a hiatal hernia, a few small erosions at the GE junction and hematin in the gastric body. Colonoscopy revealed two small (5 to 8 mm) benign appearing sessile polyps in the rectum and the cecum. Hot snare polypectomy was performed on both. The terminal ileum appeared normal. Histopathology of both polyps revealed poorly differentiated adenocarcinoma infiltrating the lamina propria predominantly in small clusters. Immunostains were subsequently positive for CK7 and negative for CK20; consistent with metastatic lesions from his lung primary. Primary lung cancer with metastasis to the GI tract is extremely rare with only a limited number of cases reported to date. It is estimated that only 20% of patients who develop distant metastases (adrenals, kidneys and abdominal lymph nodes) during their clinical course have GI tract involvement. The small intestine is the most common site for metastasis; others being the stomach and esophagus. Patients with GI metastasis can develop abdominal pain, nausea, weight loss; less frequent symptoms include bowel perforation, obstruction or peritonitis. Colonic involvement has been discovered in only 5% of patients with lung cancer, but this has been demonstrated in post-mortem studies, as the majority of the patients are asymptomatic and rarely present clinically. Patients with colonic metastasis most often present later in their disease course with anemia (as our patient did) or with lower GI bleed. We present a 68-year-old patient with an unusual presentation of metastatic lung cancer. Patients with colonic metastasis from lung cancer are rare and usually present later in their disease course. This entity should be considered for any patient with lung cancer and iron deficiency anemia.