Intraluminal Small Bowel Metastasis From Primary Lung Cancer

A Rare Presentation of Small Bowel Perforation Secondary to Microscopic Metastasis of Non-small Cell Lung Cancer (NSCLC): A Case Report

Gastrointestinal tract perforation (GITP) due to metastatic lung cancer is an exceptionally rare occurrence. Symptoms can range from mild abdominal discomfort to severe and life-threatening bowel perforation. In this case presentation, we describe an unusual instance involving squamous non-small cell lung cancer (NSCLC), where microscopic metastases in the small bowel led to bowel perforation. Our patient, a 71-year-old male with a history of stage IIIa squamous cell carcinoma in the right lung and smoking history, completed chemoradiation therapy and is currently undergoing treatment with durvalumab. He presented to the ED with complaints of abdominal pain, nausea, and abdominal distention. His review of systems revealed no other significant issues, and his vital signs were stable. However, the abdominal examination revealed noticeable distention with tenderness upon palpation and guarding. Laboratory results were significant for leukocytosis with a left shift of neutrophils and mildly elevated kidney function. A CT scan of the abdomen and pelvis revealed widespread pneumoperitoneum, indicating a bowel perforation. Consequently, the patient underwent an urgent exploratory laparotomy, during which a small bowel perforation measuring 0.6 cm x 0.3 cm in the jejunum was identified, necessitating the resection of the affected bowel segment. Intraoperative esophagogastroduodenoscopy (EGD) showed normal findings. The histopathological examination of the resected bowel revealed clusters of squamous cell carcinoma with a desmoplastic reaction, affecting the submucosal and muscular layers at the site of the defect, with surgical margins free of tumor or inflammation. This finding indicated metastatic disease originating from the known lung squamous cell carcinoma. After the operation, the patient was admitted to the ICU due to septic shock caused by E. coli and Klebsiella peritonitis, requiring intubation and circulatory support with pressors. Ultimately, he was discharged following treatment. This case underscores the rarity of symptomatic bowel perforation from micro-metastasis in squamous NSCLC and emphasizes the need for rigorous assessment and timely surgical intervention. However, it is important to recognize the significant risk of complications and a high mortality rate, leading to a challenging prognosis. As such, individuals with a known history of lung carcinoma who present with abdominal symptoms should undergo comprehensive evaluation to prevent life-threatening complications through early intervention.

Duodenal Metastasis From Primary Lung Adenocarcinoma: A Diagnostic and Therapeutic Challenge

Distant metastasis from primary lung cancer is mostly seen in the liver, brain, adrenal glands and bones. Small bowel, specifically duodenum is a relatively unusual site for distant metastasis from lung carcinoma. This case reports a rare scenario of upper gastrointestinal bleeding caused by duodenal metastasis by a primary lung adenocarcinoma. A 43-year-old woman presented to the emergency department with complaints of progressive hemoptysis for the past three weeks. Esophagogastroduodenoscopy (EGD) revealed a 2.5 cm x 2.5 cm fungating villous mass-like structure in the first portion of the duodenum, with a normal-appearing esophagus and stomach. Biopsies were performed, which were histologically consistent with poorly differentiated malignant. The immunohistochemical (IHC) staining was consistent with metastatic disease from primary lung adenocarcinoma. Due to its rarity, there are no solidified guidelines for the management of duodenal metastasis from lung carcinoma. Our case was challenging due to the extensive metastasis and low functional status of the patient and was ultimately managed with home hospice.