Diagnosis of renal lymphoma by percutaneous image guided biopsy: experience with 11 cases.

PURPOSE: We reviewed an institutional experience with image guided percutaneous biopsy of focal renal masses that yielded a diagnosis of lymphoma.

MATERIALS AND METHODS: We retrospectively reviewed the hospital records of patients undergoing percutaneous renal biopsy between September 1997 and February 2005.

RESULTS: A total of 407 image guided focal renal lesion biopsies were identified. A diagnosis of lymphoma was made in 11 patients (3%). Biopsies were performed under computerized tomography guidance in 9 cases (82%) and under ultrasound guidance in 2 (18%). Core biopsies were performed in 11 cases, while fine needle aspiration was done in 10 (91%). Fine needle aspirations underwent cytological analysis in 10 cases and flow cytometry analysis in 9. The final combined pathological diagnoses were B-cell lymphoma in 10 cases and lymphomatoid granulomatosis in 1. Analysis of core biopsies yielded a diagnosis of B-cell lymphoma in 10 cases (91%) and lymphomatoid granulomatosis in 1. Analysis of fine needle aspirations yielded a diagnosis of B-cell lymphoma in 3 cases (30%), lymphoma in 4 (40%), suspicion of lymphoma in 1 (10%), atypical cells in 1 (10%) and a nondiagnostic sample in 1 (10%). Flow cytometry concurred with cytology in the diagnosis of B-cell lymphoma in 2 cases, allowed the identification of lymphoma subtype, which was not made on cytology, in 4, was insufficient in 2 and identified no abnormality in 1. No patients underwent surgery or an ablative procedure.

CONCLUSIONS: Core biopsy has a higher diagnostic yield than fine needle aspiration for diagnosing renal lymphoma. Flow cytometry analysis adds additional diagnostic information to cytological examination of fine needle aspiration samples. Accurate diagnosis of lymphoma in these cases allowed proper treatment without unnecessary surgery or other procedures.