Background: Posttransplant lymphoproliferative disorder (PTLPD) is a relatively common complication in kidney transplant recipients. It can involve the kidney allograft itself as well as extragraft sites. It is usually suspected clinically and diagnosed by tissue biopsy. It comprises a spectrum of lesions ranging from lymphoid byperplasia to frank lymphoma.
Case: A 21-year-old male presented with recurrent episodes of microhematuria 2 years after a renal transplant. Voided urine cytology showed anaplastic, discohesive cells. Immunocytochemistry study on a urine cytospin showed the cells to be positive for LCA, CD20 and for CD79a and negative for CD3, CD15, CD30, cytokeratin, S-100 and HMB45, confirming their lymphoid origin.
Conclusion: This is a rare suspected occurrence of PTLPD in voided urine. The presumptive diagnosis was supported by immunocytochemistry. However, voided urine cytology should not be considered a standard diagnostic test due to its low sensitivity. Diagnosis and proper subclassification of kidney PTLPD should be confirmed by histologic tissue study with supportive ancillary studies--e.g., immunohistochemistry and flow cytometry.