A Rare Cause of GI Bleeding: Metastatic Lung Adenocarcinoma to the Ileum

Abstract

Lung adenocarcinoma is the most common type of lung cancer and commonly metastasizes to the bone, adrenal glands, liver, and brain. Intestinal metastasis is infrequent and clinical manifestations of this are even rarer. We present a case of metastatic adenocarcinoma to the ileum in a patient presenting with passing dark red blood from his rectum. A 60 year-old male, with past medical history of metastatic adenocarcinoma of the lung to the brain, status-post left lower lung lobectomy and craniotomy with right frontal partial lobectomy, a remote history of cerebrovascular accident on current anti-platelet therapy, and residual dysphagia on gastric tube feeds, presented to the emergency department with nausea, vomiting, and generalized weakness for 1 week. He had completed chemotherapy and radiation 3 months prior. Vomiting and loose stools occurred after feeds. Initial evaluation revealed a cachectic man with decreased air entry and rhonchi on pulmonary exam, and a soft, non-distended abdomen. Vitals were significant for hypotension, 90/50mmHg. On day 2 of hospitalization, the patient had hematochezia and a drop in hemoglobin from 8.1g/dL to 6.2g/dL. He was transfused 2 units of packed red blood cells. Gastroenterology was consulted for continued rectal bleeding and performed a colonoscopy. Blood clots were present throughout the colon and a 4 centimeter submucosal mass with ulceration of the overlying mucosa was visualized in the ileum, narrowing the lumen (Image A, B). Tattoo ink was injected proximal and distal to the lesion, and multiple biopsies were taken. He was evaluated for surgery, however given his advanced disease and multiple co-morbidities, he would not be a surgical candidate. Results of the pathology confirmed poorly differentiated adenocarcinoma, with immunohistochemistry consistent with lung primary. Hematochezia subsided and after discussion with the family, they opted for comfort care with hospice. Spread of primary lung cancer to the gastrointestinal (GI) tract has an approximate occurrence of 0.2-11.9%, with clinical manifestations in 0.2-0.5% of the cases. The small bowel is the most common site of metastasis in the GI tract. It is critical to suspect and evaluate for metastatic disease in patients with advanced lung adenocarcinoma who present with GI symptoms.Figure: A. Blood clots seen throughout colon.Figure. 4: cm ileal submucosal mass with ulceration.