Renal biopsy is a helpful tool for the diagnosis of POEMS syndrome

Abstract

A 57-year-old Japanese male was admitted to our hospital for pleural effusion, massive ascites, and leg edema in March 2010. Upon physical examination, hyperpigmentation, hemangioma, and gynecomastia were noted. The patient had no neurological symptoms, but tendon reflexes were absent. Urinalysis showed 2 proteinuria and 2 hematuria. Chest radiograph showed cardiomegaly and bilateral pleural effusion. Computed tomography of the abdomen revealed hepatosplenomegaly, and massive ascites. Blood examination showed moderate renal dysfunction (serum creatinine 1.81 mg/dl, blood urea nitrogen 44 mg/ dl). A small amount of monoclonal protein was detected, and serum protein immunoelectrophoresis revealed this to be IgA-k M protein (1295 mg/dl). There were 5.4 % plasma cells in bone marrow aspirate and biopsy, but hematopoiesis was otherwise normal. The low concentration of M protein was unusual for multiple myeloma, and examination of the bone marrow did not reveal neoplastic plasma cell. Moreover, there were no plasmacytomas. Systematic amyloidosis, the result of deposition of abnormal light chain in tissues was considered. To develop a definitive diagnosis, percutaneous renal biopsy was performed, revealing enlarged glomeruli with mild proliferation of mesangial cells and segmental mesangiolysis. This glomerular alteration resembled membranoproliferative glomerulonephritis (MPGN) in appearance (Fig. 1a). Electron microscopy showed widening of the subendothelial and mesangial area, with widespread deposition of amorphous material (Fig. 1b), histological findings consistent with the typical histology of POEMS syndrome. After the renal biopsy, POEMS syndrome was suspected and his massive ascites was thought to be due to this syndrome. Plasma VEGF level was elevated (700 pg/ml; normal \117 pg/ml). Motor nerve conduction studies performed in the median nerve showed mild decrease in the nerve conduction velocities. The association of polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes led to the diagnosis of POEMS syndrome. The patient had three major criteria (including two mandatory) and five minor criteria of the current Mayo Clinic criteria for the diagnosis of POEMS syndrome [1]. Here, we report a patient with POEMS syndrome whose renal biopsy led us to an appropriate diagnosis. In POEMS syndrome, the presenting symptoms are variable and sometimes difficult to diagnose. POEMS syndrome is also known to show unique features in renal biopsy, such as MPGN-like lesions and mesangiolytic glomerulonephritis. Electron-lucent subendothelial space in glomerular capillaries by electron microscopy has been found to be a characteristic feature in POEMS syndrome [2]. Our experience in this case indicates that renal biopsy may be helpful for the diagnosis of POEMS syndrome.