Diagnosis of canine renal lymphoma by cytology and flow cytometry of the urine

Abstract

Lymphoma is a common hematopoietic neoplasm of dogs. A definitive diagnosis typically requires the collection of samples via fine‐needle aspirate or biopsy. A unique case of canine renal T‐cell lymphoma diagnosed using urine sediment microscopy with flow cytometry and PCR for Antigen Receptor Rearrangement (PARR) is presented. A fresh urine sample was collected via a urinary catheter and immediately prepared for cytologic examination, flow cytometry, and PARR. The flow cytometric study revealed that 83% of the cells were large CD3+CD8+ T cells, while PARR identified a clonally rearranged T‐cell receptor gene, supporting the flow cytometry findings. Despite supportive care, the patient progressed to anuric renal failure and was humanely euthanized. A necropsy was performed, and tissues from the upper and lower urinary tracts were collected. Histologically, the right and left kidneys were infiltrated by a neoplastic round cell population effacing the cortex and medulla. Immunohistochemistry for the T‐ and B‐cell antigens CD3 and CD20, respectively, revealed that the neoplastic population within the kidney demonstrated diffuse, strong, membranous to intracytoplasmic CD3 expression while lacking CD20 expression. These results confirmed the diagnosis of renal T‐cell lymphoma. This is the first known report of canine lymphoma diagnosed using either urine flow cytometry or clonality testing. Therefore, in select cases, urine flow cytometry and/or PARR are feasible to perform on urine‐derived cells as a quick and cost‐effective means to aid in the diagnosis of urinary tract lymphoma.

Urinary bladder wall mass with neoplastic lymphoid cells in the urine: Diagnosis of an IgG secretory B‐cell lymphoma with Bence‐Jones proteinuria in a dog

“…A recent case report described using flow cytometry and PARR on urine for the diagnosis and characterization of renal T-cell lymphoma, but the urine sample, in this case, did not need to be shipped and was rapidly concentrated, washed, and analyzed, precluding a thorough discussion on preservation techniques. 15 Serum protein electrophoresis and UPE indicated a secretory B-cell lymphoid neoplasm. The serum M-protein was labeled with IgG-FC, IgG4, and light chain reagents.…”

“…None of these cases of primary urinary bladder extranodal lymphoma were diagnosed by flow cytometry and/or PARR. A recent case report described using flow cytometry and PARR on urine for the diagnosis and characterization of renal T‐cell lymphoma, but the urine sample, in this case, did not need to be shipped and was rapidly concentrated, washed, and analyzed, precluding a thorough discussion on preservation techniques 15 …”

“…12 Another case involved a 10-year-old male neutered Brittany Spaniel with renal involvement and disease diagnosed by flow cytometry and PARR of fresh urine; this case failed to respond to "supportive care" and was euthanized. 15 There is also a single case report of feline urinary bladder B-cell lymphoma diagnosed by urine cytology, histology, and immunohistochemistry; this case had concurrent involvement of the gall bladder. 13 The cat had a protracted history of hyperglobulinemia, suggesting a more indolent course but failed to respond to a CHOP-based chemotherapy protocol (cyclophosphamide, prednisolone, vincristine, doxorubicin, and lomustine), suggesting a more aggressive or advanced disease state at the time of diagnosis, similar to our case.…”

Imaging features of unilateral renal T‐cell lymphoma occurring simultaneously in the urinary bladder wall and contralateral ureter with secondary polycythaemia in a dog

“…5 Recently, urine flow cytometry has been reported to be a feasible method to aid in the diagnosis of urinary tract lymphoma. 22 In our patient, the images obtained by CT offered greater detail of the lesions than the observed with ultrasound, their dimensions and degree of vascularization among others, specifically regarding the bladder and ureter tumour, in addition to better characterizing the morphology and internal architecture of the mass of the right kidney, facts that could not be accurately assessed by ultrasound. Hence, the information of the lesions obtained by means of contrast-enhanced CT helped in the understanding of the characteristics of the pathologies found, especially if we take into account that it has been the first description of this type of tumour at the level of a ureter.…”

“…In the present case, a flow cytometry assay and polymerase chain reaction clonality assay were used to assess the lymphoid population which indicated a T‐cell origin 5 . Recently, urine flow cytometry has been reported to be a feasible method to aid in the diagnosis of urinary tract lymphoma 22 …”