Gastrointestinal metastases from malignant tumors of the lung

Autopsy data of 423 cases of primary tumor of the lung over a 36-year period were evaluated for the presence of gastrointestinal tract metastases. Fifty-eight cases (14%) were found and were analyzed for histologic nature of tumor, anatomic location, symptomatology and complications. The most common histologic type of lung tumor causing gastrointestinal tract metastasis was squamous cell (19 cases, 33%), followed by large cell (17 cases, 29%), and oat cell (11 cases, 19%). The esophagus was the most common site of involvement (33 cases). Fourteen of the 33 cases were involved by direct extension of the tumor. The middle third of the esophagus had metastases more commonly (16/33, 49%) than the other two sites. Most patients with gastrointestinal metastases had no symptoms. In those patients with symptoms, dysphagia was most common when the tumor involved the proximal gastrointestinal tract (esophagus, stomach), whereas, pain was most commonly seen with involvement of the distal gastrointestinal tract (small bowel, large bowel). Six of 20 patients (30%) with small bowel involvement experienced perforation and peritonitis as complications of metastatic involvement and two patients with large bowel metastasis had obstruction; a third had dehiscence of a previous anastomotic site. Gastrointestinal tract metastases from primary carcinoma of the lung are more common than previously thought and may be associated with serious clinical complications.