International Journal of Surgical Pathology 8(4):329-331, 2000 Massive Exfoliation of Markedly Atypical Cells in Urine Resulting from Polyoma Virus

Polyoma virus nephritis is increasingly being recognized as a cause of allograft dys-function in renal transplant patients. We describe and illustrate the findings in a re-nal biopsy and a concurrent urine sample from a patient with polyoma virus nephri-tis. The urine cytology findings were highly suggestive of a tumor due to the presence of large number of atypical cells with marked hyperchromasia, high nuclear/cyto-plasmic ratio in a necrotic background. Scattered cells with viral cytopathic changes were also identified, therefore indicating an infectious process with associated reac-tive cellular changes rather than a tumor. The cytological findings could thus be ex-plained by the viral cytopathic and cytolytic changes, as well as marked reactive and degenerative changes in tubular epithelial cells. Int J Surg Pathol 8(4):329-331, 2000 Key words: renal transplant, BK virus, urothelial malignancy, urine cytology. The patient here presented is a 64-year-old man with end-stage renal disease secondary to hyperten-sion who received a cadaveric renal transplant 14 months ago. After the transplant, the patient ha