Decoy cells and malignant cells coexisting in the urine from a transplant recipient with BK virus nephropathy and bladder adenocarcinoma

Abstract

The search for decoy cells (DC) in urine is widely used as screening for BK virus (BKV) reactivation in transplant recipients. BKV cytopathic effect of DC must not be confused with high-grade urothelial carcinoma. This report presents a case of coexistence of DC and malignant cells in the urine from a transplant recipient with BKV-associated nephropathy (BKVN) and bladder adenocarcinoma. A 38-year-old female with type 1 diabetes mellitus and end-stage renal disease underwent a simultaneous pancreas and kidney transplant. Four years post-transplantation, BK virus studies were performed for renal dysfunction. Isolated DC and DC in casts were identified in urine. Also, the tests for BKV DNA were positive in serum and renal allograft biopsy. BKVN was treatment-resistant and the patient returned to hemodialysis. A kidney transplant nephrectomy was performed 2 years later. The next urine cytology showed, in addition to DC, other distinct cells with nuclear atypia highly suggestive of malignancy. Some cells showed both, malignant and DC features. A bladder adenocarcinoma was diagnosed on biopsy and BKV proteins were demonstrated on tumor cells, supporting a possible role for BKV in the oncogenic pathway in this clinical setting. The presence of DC in the urine from a transplant recipient is the hallmark of BKV activation, but it does not exclude the existence of carcinoma. Furthermore, the presence of highly atypical cells should raise, not eliminate, the possibility of neoplastic transformation of the bladder.

Polyomavirus (BK)-associated pleomorphic giant cell carcinoma of the urinary bladder: a case report

“…Decoy cells and urothelial carcinoma cells have been previously reported in the same urine specimen [26]. Indeed, involvement of BKV in the pathogenesis of human urothelial tumors has been suggested by some studies, but is not conclusively resolved [1,8,9,11,13,14,16,23,24,26].…”

“…The introduction during the past two decades of new more potent immunosuppressive regimens has led to a significant increase in BKV-associated pathology, including but not limited to BKV allograft nephropathy (BKAN), ureteral stenosis, and hemorrhagic cystitis [5,10]. Although the cytologic features of BKV urinary tract infection (decoy cells) are well described [5], the literature describing BKV-associated urinary tract malignancies is scant, and the role of BKV in the development of human urinary tract tumors is still debated [1,5,[8][9][10][11]13,14,16,23,24,26].…”

Unusual BK polyomavirus‐associated urologic malignancies in renal transplant recipients: Report of two cases and review of the literature

“…However, the most serious complication of BKV in these patients is the development of urologic malignancies. Fortunately, such complications are rare and only 36 cases of urothelial carcinoma (UC) (Table ), and several renal cell carcinomas, including collecting duct carcinomas were reported to date …”

“…Many pathologists consider the presence of the so‐called decoy cells to preclude a diagnosis of UC as atypia may be ascribed to the cytopathic effects of BKV. However, decoy cells and malignant urothelial cells can co‐exist as shown in cases described in Table . Occasionally, HGUC cells can have features like jet black and smooth or glassy chromatin similar to decoy cells .…”

Renal Cell Carcinoma in the Allograft: What Is the Role of Polyomavirus

“…Besides the correlation between BKVN and graft failure, a small number of case reports suggest an association between BKV infection and the development of renal and bladder cancers in renal transplant recipients [7, 8, 9, 10, 11, 12, 13, 14] ( table 1 ). Indeed, for more than 30 years, an oncogenic potential of BKV has been observed in vitro and in animal models [3, 15, 16].…”