We have experienced case involving a 63-year-old patient with a pulmonary carcinoma, who was given an enterectomy following a lobectomy, due to minimal intestinal metastasis. In this case, using flow cytometry, the cancer cell nuclear DNA content was analyzed for the primary tumor focus, the mediastinal lymph node metastatic focus, and the small intestinal metastatic focus. For the primary focus, a cancer cellular population of polyploidy with 2 ploidies of DNA content was observed, while for both the metastatic foci, only a single cancer cellular population was observed, indicating the heterogeneity of the nuclear DNA content between the primary focus and metastatic foci. These 2 metastatic foci had DNA contents completely corresponding to that for a ploidy with a high DNA content in the primary focus, suggesting a metastasis of only the above population from the primary focus. The present case apparently formed metastatic foci in other organs than the lungs but only by cancer cells more susceptible to metastasis among the cancer cells found in the primary focus.