Renal lymphoma - The diagnostic and therapeutic roles of fine-needle aspiration

This study focused on 19 patients with renal lymphoma (RL) from whom 20 ini tial (1 patient with fine-needle aspiration [FNA] specimens of masses in bo th kidneys) and 1 repeated FNA specimen were obtained. Of the 19 patients, 10 had secondary RL, 8 primary RL, and 1 transplant RL. The FNA samples wer e studied by smears tall cases), tissues (II), phenotyping by immunostainin g (13) or flow cytometry (4), and gene rearrangement (3). The final diagnos es included 1 T-cell lymphoma and 18 B-cell lymphomas. Of the 20 original s pecimens, 14 were reported as positive for lymphoma, 3 suggestive of lympho ma, 1 positive for transitional cell carcinoma, and 2 unsatisfactory. The f ollow-up specimen showed reactive changes. Tissue correlation, available in 11 cases, confirmed a positive cytodiagnosis (7), provided a final diagnos is in the cytologically inconclusive cases (3), or revised the misdiagnosis of transitional cell carcinoma from smears (1). The phenotyping elucidated the B vs T lineage of the lymphoma in all tested cases, confirmed the posi tive cytodiagnosis in 10 cases, confirmed the reactive cytodiagnosis in 1 c ase, and helped achieve a conclusive diagnosis in 2 cases suggestive of lym phoma. Gene rearrangement studies showed light chain restriction in the 2 t ested cases. FNA has an essential role in treatment planning for RL. Althou gh FNA usually is diagnostically conclusive, a high index of suspicion and awareness of atypical or misleading cytomorphologic features are important for a correct interpretation, especially for primary RL. Ancillary testing is essential for the diagnosis in problematic cases and lays the foundation for the differential diagnosis.