A 73-year-old man was referred for the investigation of positive urine cytology and right lumbar pain. Contrast-enhanced computed tomography (CT) showed a tumor in the upper right kidney (Picture 1A) and lung masses (Picture 1B, arrows). Positron emission tomography-CT showed an increased radionuclide uptake in the kidney (Picture 2A), lymph nodes (Picture 2B, arrows), pancreas (Picture 2C, arrows), lungs, bones, and rectum (Picture 2D, arrows). Colonoscopy showed a 10-mm type 0-IIa+IIc rectal tumor. The IIa part was erythematous with a dilated tortuous vessel pattern but magnifying endoscopy did not show an irregular pit pattern (Picture 3). A histological examination of a biopsy specimen from the tumor margin suggested urothelial cancer; immunohistochemical results were positive for cytokeratin 7 but negative for cytokeratin 20 (Picture 4). These findings yielded a final diagnosis of Stage IV renal pelvic cancer. To our knowledge, this is the first report of metastasis of renal pelvic cancer to the rectum mimicking primary colorectal cancer (1,2).
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The authors state that they have no Conflict of Interest (COI).
References
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