What are the possible false positive and false negative findings on CT for transitional cell carcinomas (TCCs)?

Updated: Aug 21, 2016
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD  more...
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Answer

Answer

In stage I or II disease, conditions such as chronic pyelitis, tuberculosis, and xanthogranulomatous pyelonephritis may mimic TCC.

In stage III or IV disease, CT cannot be used to distinguish edema, infection, inflammatory changes, or hemorrhage from tumor. All of these processes may cause inhomogeneous peripelvic attenuation that is indistinguishable from that caused by the infiltration of fat by tumor. Superimposed pyelonephritis can cause inhomogeneous renal enhancement and thus give a false interpretation of invasion by underlying TCC. Occasionally, renal cell carcinoma may simulate TCC with renal parenchymal infiltration.

The characteristic attenuation of a TCC lesion is normally sufficiently different from renal tract filling defects of other causes, such as calculi and blood clots, to enable the correct diagnosis. However, a blood clot may be confused with a hyperattenuating TCC, particularly in the early stages of the disease. Also, in a patient with undiagnosed early-stage TCC, inhomogeneous renal fat attenuation of any cause may hinder accurate diagnosis.


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