Abstract
Waldenström's disease is a rare lymphoproliferative syndrome in the bone marrow and sometimes in lymphoid organs which secretes high amounts of monoclonal immunoglobulin M into serum. It can remain indolent for years and rarely affects the kidney, with intraglomerular rather than intratubular damage being predominant, in contrast to multiple myeloma. Different studies identified AL amyloidosis as the most frequent renal lesion, followed by cryoglobulinemic glomerulonephritis. Signs and symptoms may be unspecific, as well as renal manifestations, so collaboration between nephrologists, hematologists, and pathologists is crucial to establish the role of paraprotein in the development of renal damage. We present an atypical case of Waldenström's disease that had a minimal monoclonal peak and clinically debuted with nephritic and nephrotic syndromes. The diagnosis was cryoglobulinemic glomerulonephritis. Currently, there are numerous treatment options, without enough evidence yet to establish a standardised treatment.