Ardalan Mohammad Reza, Shoja Mohammadali Mohajel
Department of Nephrology, Dialysis and Renal Transplantation, Tabriz University of Medical Sciences, Tabriz, Iran.
Am J Hematol. 2007 Apr;82(4):309-13. doi: 10.1002/ajh.20796.
Acute interstitial nephritis and rheumatoid arthritis (RA) or RA-like polyarthritis are among the very rare paraneoplastic manifestations of multiple myeloma (MM). A 47-year-old man with acute renal failure due to interstitial nephritis was admitted to our university hospital and successfully treated with corticosteroid. He later developed a symmetric distal polyarthritis with morning stiffness mimicking RA. On follow-up, the patient had a rise in serum creatinine, hypercalcemia, anemia, and a monoclonal spike (Bence Jones protein) on the urine protein electrophoresis. Bone marrow biopsy demonstrated a diffuse neoplastic plasma cell infiltration. Diagnosis of MM was made and the patient received chemotherapy. After four-course chemotherapy, the patient's articular manifestations resolved, urine monoclonal spike disappeared, and serum creatinine returned to a near normal level. We hypothesize that in this case, immunologic hypersensitivity reactions to the light-chain molecules or other tumoral antigens deposited within the kidney or joint spaces, in the context of MM cytokine milieu may have resulted in this unusual presentation. Ultimately, clinicians and pathologists should consider MM in the differential diagnosis of the acute interstitial nephritis and RA-like polyarthritis.
急性间质性肾炎与类风湿关节炎（RA）或类RA多关节炎是多发性骨髓瘤（MM）极为罕见的副肿瘤表现。一名因间质性肾炎导致急性肾衰竭的47岁男性入住我们大学医院，经皮质类固醇治疗成功。他后来出现了对称性远端多关节炎，伴有晨僵，类似RA。随访中，患者血清肌酐升高、高钙血症、贫血，尿蛋白电泳出现单克隆峰（本周氏蛋白）。骨髓活检显示弥漫性肿瘤性浆细胞浸润。确诊为MM，患者接受了化疗。经过四个疗程的化疗，患者的关节表现消失，尿单克隆峰消失，血清肌酐恢复到接近正常水平。我们推测，在本例中，在MM细胞因子环境下，对沉积在肾脏或关节间隙中的轻链分子或其他肿瘤抗原的免疫超敏反应可能导致了这种不寻常的表现。最终，临床医生和病理学家在急性间质性肾炎和类RA多关节炎的鉴别诊断中应考虑MM。
