Renal MALT lymphoma associated with Waldenström macroglobulinemia.

Mucosa associated lymphoid tissue lymphoma (MALT lymphoma) is mostly seen in the gastrointestinal tract; origin from the kidney is extremely rare. Waldenström macroglobulinemia (WM) is a clinicopathologic syndrome denoted by the presence of monoclonal gammopathy in the serum, typically caused by lymphoproliferative disorder. Literature review did not find any report of renal MALT lymphoma accompanied by WM. Herein, for the first time, we report a 72 year-old female patient with a history of chronic kidney disease, presenting with solitary renal mass; MALT lymphoma was confirmed by pathological examination. A serology study identified the presence of WM. No manifestation of hyperviscosity syndrome was noted. Bone marrow biopsy disclosed the concurrent systemic involvement. Her treatment response was uneventful and the renal mass responded with regressive change in size after chemotherapy. The renal function remained stable during follow-up. MALT lymphoma should be considered as an underlying pathology of isolated renal mass. Furthermore, patients with MALT lymphoma should be screened for Waldenström macroglobulinemia and hyperviscosity syndrome.