Case
178 Diagnosis |
 |
|||
Versión
en Español |
|||
Go back to clinical information and images
Diagnosis: Polyomaviris Nephropathy (with decoy cell casts)
It is relatively common to find "decoy cells" in the urine of renal transplant patients, mainly during the first year, some authors say that in about 20% of transplant patients, a finding that is considered not very specific for Polyomavirus nephropathy, since most of these cases will correspond to reactivation in the urothelium. However, in the case that we present, cellular casts were evident, in whose cells there were nuclear inclusions, this finding would indicate that the infected cells come from the kidney, since the casts are formed in the renal tubules. A finding related to the so-called “Haufen” (from the German word for “cluster or stack”), described in electron microscopy studies (Singh HK, et al. Presence of urinary Haufen accurately predicts polyomavirus nephropathy. J Am Soc Nephrol. 2009;20:416-27. [PubMed link]).
This finding in the cytological study of urine (casts with inclusions) is not very frequent and in the available literature there are few articles indicating that this finding greatly increases the specificity for diagnosing renal involvement by the virus. From our point of view, it is a finding of great diagnostic value and should be considered as a sign of polyomavirus nephropathy.
Although decoy cells in urine has poor specificity, the positive predictive value of urine cytology can be further increased to over 90% by taking additional parameters into consideration: (a) a “dirty” cytological background, (b) decoy cell shedding in the setting of allograft dysfunction, (c) extended and persistent decoy cell shedding over more than 6 weeks, and (d) the detection of decoy cell casts (Singh HK, et al. Urine Cytology Findings of Polyomavirus Infections. In: Madame Curie Bioscience Database [Internet] [Link]).
In the renal biopsy of the patient in our case, Polyomavirus nephropathy was confirmes, with abundant inclusions and multiple cell casts with these inclusions.
See the chapter: Poliomavirus Infection of our Tutorial (only Spanish version).
Go back to clinical information and images
References
- GXing J, Procop GW, Reynolds JP, Chiesa-Vottero A, Zhang Y. Diagnostic utility of urine cytology in early detection of polyomavirus in transplant patients. J Am Soc Cytopathol. 2017;6(1):28-32. [PubMed link]
- Gouvêa AL, Cosendey RI, Carvalho FR, et al. Pilot Study of Early Monitoring Using Urinary Screening for BK Polyomavirus as a Strategy for Prevention of BKV Nephropathy in Kidney Transplantation. Transplant Proc. 2016;48(7):2310-2314. [PubMed link]
- Ranzi AD, Introíni GO, Prolla JC, et al. Correlation between the presence of degenerated inclusion-bearing cells in voided urine samples and the occurrence of polyomavirus infection. Cytopathology. 2017;28(2):103-108. [PliubMed link]
- Chen TW, Chen CY, Lin NC, King KL, Wu TH, Yang WC, Loong CC. How to Improve the Positive Predictive Value of Urinary Decoy Cell Surveillance for Polyomavirus BK-Associated Nephropathy in Kidney Transplant Patients. Transplant Proc. 2016;48(3):924-8. [PubMed link]
- Singh HK, Bubendorf L, Mihatsch MJ, et al. Urine Cytology Findings of Polyomavirus Infections. In: Madame Curie Bioscience Database [Internet]. Austin (TX): Landes Bioscience; 2000-2013. Available from: https://www.ncbi.nlm.nih.gov/books/NBK6541/
- Singh HK, Andreoni KA, Madden V, True K, Detwiler R, Weck K, Nickeleit V. Presence of urinary Haufen accurately predicts polyomavirus nephropathy. J Am Soc Nephrol. 2009;20(2):416-27. [PubMed link]