A case of rectal carcinoma metastasis with polypoid growth in the pulmonary artery

Abstract

The patient was a 52-year-old woman previously diagnosed with rectal carcinoma. In June 2001, she underwent low anterior resection and partial resection of the liver simultaneously at another hospital. In September 2004, she received rectal amputation due to local recurrence in the pelvis. In 2008, an abnormal shadow in the left pulmonary artery (A¹⁺²c) was identified on chest computed tomography. Since this was considered to be a benign vascular lesion, no further examination was conducted, and she had been conservatively followed-up. However, the size of the lesion continued to increase gradually. In April 2013, the lesion was still confined inside the pulmonary artery, but its size had increased to 4.5 cm. As a result, she consulted our department. We reviewed the patient's previous chest computed tomography findings at the previous hospital, and found that the small shadow had been present since October 2005. We then performed positron emission tomography, and the lesion showed the accumulation of FDG (SUV max=17.1). Since the lesion was suspected to be malignant, we performed left upper lobectomy in June 2013. Histopathological examination revealed that the intravascular lesion was a metastasis from rectal carcinoma. The tumor tissue was found to exist only inside the pulmonary artery, and the vascular wall had been partially invaded.