Metastatic carcinoma suggestive of urothelial carcinoma in the absence of known high-stage urothelial carcinoma: Analysis of clinical and pathologic parameters
Onwubiko I, Rodgers S, Oyedeji O, Taneja K, Hassan O, Gupta N, and Williamson S. Metastatic carcinoma suggestive of urothelial carcinoma in the absence of known high-stage urothelial carcinoma: Analysis of clinical and pathologic parameters. Modern Pathology 2020; 33(3):950.
Background: Urothelial carcinoma that is pT2 or higher is known to be an aggressive disease. However, we have encountered occasional biopsies of metastatic carcinoma with features suggestive of urothelial carcinoma in patients who have no known high-stage primary tumor. Design: We searched our pathology database for reports indicating metastatic carcinoma with findings suggesting urothelial carcinoma. Clinical and pathologic data were reviewed to identify patients without a known high-stage primary tumor. Results: Search identified 272 specimens showing metastatic carcinoma suggestive of urothelial carcinoma. Of these, 14 patients had no known primary tumor of pT2 or higher on comprehensive pathology and electronic medical record review, including 10 (71%) pT1, 3 (21%) carcinoma in situ, and 2 (14%) pTa. A substantial number (n=8, 57%) had tumors of the renal pelvis (n=5), ureter (n=1), or prostatic urethra (n=2). Metastatic sites included the lungs (n=4), liver (n=4), bone / soft tissue (n=3), brain (n=2), and lymph nodes (n=2). Unique patients included one with a renal pelvis high-grade papillary urothelial carcinoma concurrent with multiple sites of clear cell adenocarcinoma thought to be also of urinary tract origin. Another patient had prominent inflammatory / myxoid changes surrounding the ureter that was resected to relieve obstruction; however, no carcinoma was sampled in this specimen. Conclusions: A high proportion of patients with metastatic carcinoma suggestive of urothelial carcinoma in the absence of a high-stage primary tumor (pT2 or higher) have had a primary tumor in uncommon sites, including the renal pelvis, prostatic urethra, or ureter (57%). This raises the possibility that current staging parameters and pathologic evaluation for non-bladder primary tumors are not entirely adequate for assessing their risk.