Isolated colonic metastasis two years after resection of stage IA primary adenocarcinoma of the lung: A case report.

Colonic metastasis from lung cancer is rare, generally asymptomatic and usually develop at advanced cancer stages. Here, we report a case with a resected stage IA lung adenocarcinoma in a 51yo male patient that presented two years later with mild abdominal pain due to intestinal obstruction caused by a metastatic colon tumor. The patient underwent colonoscopy followed by surgical resection and the pathologic report was adenocarcinoma which was the same as that from a lung nodule that was excised two years earlier. Immunohistochemistry was cytokeratin 7 (CK7) positive, thyroid transcription factor 1 (TTF1) focally positive and cytokeratin 20 (CK20), caudal-related homeobox transcription factor 2 (CDX2) negative on both lung biopsy and colon surgical specimens. Interestingly there was no obvious lung cancer recurrence both at the time of metastasis and one year following chemotherapy.