Aim: Metastases from lung cancer to gastrointestinal tract are not rare at postmortem studies but the development of clinically significant symptoms from the gastrointestinal metastases is very unusual.
Methods: Formalin-fixed, paraffin-embedded tissues were cut into 5 microm thick sections and routinely stained with hematoxylin and eosin. Some slides were also stained with Alcian-PAS. Antibodies used were primary antibodies to pancytokeratin, cytokeratin 7, cytokeratin 20, epithelial membrane antigen, vimentin, smooth muscle actin and CD-117.
Results: We observed three patients who presented with multiple metastases from large cell bronchial carcinoma to small intestine. Two of them had abdominal symptoms (sudden onset of abdominal pain, constipation and vomiting) and in one case the tumor was incidentally found during autopsy. Microscopically, all tumors showed a same histological pattern and consisted almost exclusively of strands and sheets of poorly cohesive, polymorphic giant cells with scanty, delicate stromas. Few smaller polygonal anaplastic cells dispersed between polymorphic giant cells, were also observed. Immunohistochemistry showed positive staining of the tumor cells with cytokeratin and vimentin. Microscopically and immunohistochemically all metastases had a similar pattern to primary anaplastic carcinoma of the small intestine.
Conclusion: In patients with small intestine tumors showing anaplastic features, especially with multiple tumors, metastases from large cell bronchial carcinoma should be first excluded, because it seems that they are more common than expected.