Fine needle aspiration cytology diagnosis of primary renal lymphoma involving the pleura: a case report.

Background: Primary renal lymphoma is a rare disease (< 1% of kidney lesions). We present a case of renal large B-cell type non-Hodgkin's lymphoma (NHL) with right sided pleural involvement.

Case: A 70-year-old man was admitted with persistent, painless, macroscopic hematuria for 1 month. Ultrasound examination, abdominal computed tomography and magnetic resonance imaging techniques revealed a large tumor in the right kidney extending in the perirenal area. The patient underwent a radical nephrectomy for suggested renal cell carcinoma. He developed thoracic pain and pleural effusion in the 10 days after surgery. The pleural fluid was cytologically processed using conventional and ThinPrep (Cytyc Corporation, Boxborough, Massachusetts, U.S.A.) cytopreparatory techniques, slides were Papanicolaou and Giemsa stained, and immunocytochemistry was performed on the ThinPrep slides. The cytologic examination of the fluid specimen revealed a highly cellular smear composed of dispersed neoplastic cells of intermediate and large size. Immunocytochemically, the neoplastic cells were: CD45 (LCA) (+), CD20 (+), CK7 (-), CK20 (-), NSE (-), CD45 RO (UCHL-1) (-) and CD30 (-). On cytomorphologic and immunocytologic examination, the specimen fulfilled the criteria of a large B-cell type NHL. Histologic evaluation of the nephrectomy specimen revealed an infiltrating, diffuse large cell renal NHL, B-cell type, of immunoblastic and centroblastic morphology. This NHL was considered a renal primary because no peripheral lymphadenopathy or hepatosplenomegaly was revealed by the imaging techniques.

Conclusion: Cytomorphologic and immunocytologic examination revealed the typical features of a renal large B-cell type NHL in a case with pleural involvement.