Gastrointestinal Bleeding: A Rare Presentation of Gastrointestinal Metastases From Primary Carcinoma of the Lung

Abstract

Lung cancer has the highest mortality rate amongst any other cancer. About half of patients with primary lung cancer have metastases at the time of diagnosis. Metastases to the gastrointestinal tract (GI) are rare but when they do occur manifestations from bowel perforation are common and GI hemorrhage is exceedingly rare. We present two cases of patients who presented with overt gastrointestinal bleeding secondary to metastatic lung cancer involving the proximal small bowel. Case1: A 54-year-old male and active smoker presented to the emergency department with complaints of fatigue and black stool for 1 week. The patient also noted 20 pound unintentional weight loss in the last 4 months. Denied any prior endoscopies. Physical exam remarkable for melena on digital rectal exam. Labs notable for anemia with hemoglobin of 6.0 gm/dL. An emergent esophagogastroduodenoscopy (EGD) revealed a 10 millimeter, doughnut-shaped, ulcerated nodule in the duodenum with dried blood (see Figure 1). Pathology showed a metastatic poorly differentiated pulmonary adenocarcinoma. Colonoscopy was unremarkable. A Computed Tomography (CT) scan of the chest showed a large mass in the left upper lung lobe and pathology revealed poorly differentiated pulmonary adenocarcinoma. Case 2: A 78-year-old Chinese male and active smoker, presented to the emergency department with generalized weakness, dark stools, and 15 pound unintentional weight loss over the last 2 months. Normal EGD and virtual colonoscopy 3 months prior. Physical exam remarkable for melena on digital rectal exam. Labs notable for anemia with hemoglobin of 6.2gm/dL. An EGD and a colonoscopy were performed and were unremarkable. Capsule endoscopy revealed a bleeding jejunal mass. A push enteroscopy showed a circumferential, necrotic mass in the proximal jejunal that was partially obstructing the lumen and actively oozing blood. An exploratory laparotomy found a necrotic mass in the proximal jejunum that was penetrating the serosa and adherent to the mid transverse colon (see Figure 2). A segmental resection of the penetrating small bowel mass and mid transverse colon was performed. Pathology revealed metastatic, poorly differentiated pulmonary adenocarcinoma with neuroendocrine differentiation. A CT scan of chest showed a large mass in the left upper lung lobe and pathology revealed a non-small-cell undifferentiated carcinoma of the lung with neuroendocrine expression. This was consistent with the jejunal lesions being metastases from primary lung carcinoma. Our cases are unique since this is the first reported case series of undiagnosed metastatic lung cancer involving the proximal small bowel in patients admitted with overt gastrointestinal bleeding. In both cases diagnosis of lung cancer was made by histological examination of the gastrointestinal lesions, which prompted further pulmonary work-up.Figure 1Figure 2