A case of endocapillary proliferative glomerulonephritis with macrophages phagocytosing monoclonal immunoglobulin lambda light chain |
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Authors: | Hirofumi Watanabe Yutaka Osawa Shin Goto Masato Habuka Naofumi Imai Yumi Ito Takayuki Hirose Takaaki Chou Ryuji Ohashi Akira Shimizu Takashi Ehara Takashi Shimotori Ichiei Narita |
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Affiliation: | 1. Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan;2. Department of Internal Medicine, Niigata Rinko Hospital, Niigata, Japan;3. Department of Internal Medicine, Niigata Cancer Center Hospital, Niigata, Japan;4. Department of Pathology, Nippon Medical School, Tokyo, Japan;5. Department of Pathology (Analytic Human Pathology), Nippon Medical School, Tokyo, Japan;6. Graduate School of Health Sciences, Department of Health and Sport Science, Matsumoto University, Matsumoto, Japan |
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Abstract: | Multiple myeloma (MM) is a plasma‐cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33‐year‐old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M‐spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy‐associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal‐storing histiocytosis. |
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Keywords: | crystal‐storing histiocytosis endocapillary hypercellularity membranoproliferative glomerulonephritis monoclonal gammopathy‐associated proliferative glomerulonephritis multiple myeloma |
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