[Retrospective analysis of progression to multiple myeloma or related disorders in 114 patients with monoclonal gammopathy of undetermined significance in a single institute].

In 114 patients with monoclonal gammopathy of undetermined significance (MGUS) followed-up in Tachikawa Sougo hospital, we retrospectively analyzed progression of their disease to multiple myeloma (MM) or related disorders. The analysis was based on a total of 1,170 person-years of follow-up in a cohort with a median age at diagnosis of MGUS of 68 years 3 months, and with a median follow-up period of 9 years 5 months. Of these 114 patients, 13 (11%) showed progression to MM or related disorders with a median time to progression of 9 years 4 months; and the median age of these 13 patients was 78 years 8 months. The cumulative hazard ratio of progression at 5, 10, 15, and 20 years after diagnosis was 3.0%, 9.0%, 11.4%, and 32.1%, respectively. The risk of progression of MGUS to MM or related disorders in Japanese patients was as high as in Western patients studied previously, demonstrating that MGUS should be carefully monitored as a preneoplastic condition.

Simultaneous macroamylasemia and macrolipasemia in a patient with mucosa-associated lymphoid tissue lymphoma.

We report a case of simultaneous macroamylasemia and macrolipasemia complicated with mucosa-associated lymphoid tissue (MALT) lymphoma. A 78-year-old man presented with hyperamylasemia and hyperlipasemia for 2 years and was misdiagnosed with chronic pancreatitis at another hospital. However, his other pancreatic enzymes were normal, his amylase-creatinine clearance ratio was low, and no definite findings of pancreatic disease were evident. Immunological analyses revealed that both amylase and lipase were bound to immunoglobulin (Ig) A-κ, and that serum IgA was high (827.1 mg/dL). He was diagnosed with simultaneous macroamylasemia and macrolipasemia. Since these diseases are associated with malignancy, an additional investigation was performed which revealed the complication of MALT lymphoma, and polymerase chain reaction analysis showed monoclonal immunoglobulin light chain gene rearrangement (κ >> λ). In this case, macroamylasemia and macrolipasemia may have developed due to the formation of macroenzymes resulting from excess IgA-κ secreted by the MALT lymphoma. Simultaneous macroamylasemia and macrolipasemia are very rare and difficult to diagnose and can lead to diagnostic and therapeutic errors. When encountering atypical clinical features associated with hyperamylasemia and hyperlipasemia, the possibility of macroenzymes and underlying diseases such as lymphoproliferative disorders should be considered.