Probable light- and heavy-chain deposition disease in a patient with nodular diabetic glomerulosclerosis.

We report a case of probable light- and heavy-chain deposition disease (LHCDD) in a diabetic patient, a rare and educational case. The patient was a 71-year-old man having a long history of uncontrolled diabetes mellitus with retinopathy. He showed heavy proteinuria and renal insufficiency, and did not have paraproteins. Renal biopsy revealed nodular glomerulosclerosis with severe mesangial widening and microaneurysm. Immunofluorescence (IF) showed weak staining of kappa light chain, IgG and C1q along glomerular basement membrane (GBM). At first, we interpreted these IF findings to be nonspecific, thus we diagnosed as diabetic nodular glomerulosclerosis. Later, we recognized one of a few case reports of monoclonal immunoglobulin deposition disease (MIDD) in diabetic patients, and reconsidered the first diagnosis. The added electron microscopy (EM) showed obvious electron-dense materials in GBM, while tubular basement membrane deposits were not identified. A concurrence of LHCDD and diabetic nodular glomerulosclerosis may be suggested in this case. Like this case, IF staining in MIDD is often weak, so it is difficult to diagnose MIDD accurately without EM. Reports of MIDD in diabetic patients are extremely rare, possibly due to being often overlooked. This case emphasizes that overall pathological examination including IF and EM is important for the accurate differentiation of nodular glomerulosclerosis, even in diabetic patients.

A case of necrotizing glomerulonephritis presenting with nephrotic syndrome associated with pulmonary cryptococcosis.

We describe a 68-year-old man with necrotizing glomerulonephritis who presented with nephrotic syndrome accompanied by pulmonary cryptococcosis. He developed rheumatoid arthritis in July 1999 and was treated with low-dose prednisolone. He was admitted to our hospital on November 22 following the appearance of bilateral leg edema in October 2000. Laboratory tests at presentation revealed nephrotic syndrome with renal impairment. Renal biopsy specimens revealed necrotizing glomerulonephritis with crescent, but immunofluorescence study showed lack of staining for immunoglobulins or complement components. Chest X-ray and CT showed abnormal shadows in the right upper lung field, and Cryptococcus neoformans was isolated in a transbronchial lung biopsy. After the diagnosis of pulmonary cryptococcosis was made, the patient was treated with 200 mg/day fluconazole. The pulmonary abnormal shadows immediately improved and urinary protein excretion dramatically decreased. A second renal biopsy, performed about 2 months after the first biopsy, showed disappearance of crescent. Electron microscopic examination of the second renal biopsy showed partial effacement of foot processes without electron-dense deposits. Our findings suggest that necrotizing glomerulonephritis with nephrotic syndrome in this patient represented pauci-immune T-cell-mediated injury related to pulmonary cryptococcosis.