We have encountered a 49-year-old female with persistent proteinuria and hematuria. Blood pressure, renal function, physical findings and chest X-p showed no abnormality, but blood tests diclosed mild thrombocytopenia, elevated serum ACE activity, serum lysozyme activity and serum IgA concentration. Abdominal echography and CT revealed multiple nodules in her spleen. In order to make a definite diagnosis and exclude the possibilities of malignant lymphoma or metastatic malignant tumor, splenectomy, and open renal biopsy were performed at the same time. On histological examinations, light microscopic appearance of the spleen was characterized by non-caseating granulomas compatible with sarcoidosis. Renal biopsy specimen showed diffuse proliferative glomerulonephritis with positive staining of IgA predominantly located in the mesangial area, compatible with IgA nephropathy. The present case may provide suggestive evidence for a link between sarcoidosis and IgA nephropathy in the pathogenesis. IgA nephropathy complicated by sarcoidosis is rare, and thus is of particular interest because common immunological abnormalities might be considered in the disease process of both diseases. We feel that despite a low index of suspicion, physicians must be alert to the possibility of IgA nephritis associated with sarcoidosis. The literature is reviewed regarding the relationship between IgA nephropathy and sarcoidosis.
