[A case of primary amyloidosis associated with giant cell infiltration within a Bowman's capsule].

: A 67-year-old man was hospitalized with a diagnosis of nephrotic syndrome. Physical findings at admission were generalized edema and macroglossia. Urinalysis showed massive proteinuria, + +occult blood, and granular and broad casts. Ig A lambda monoclonal gammopathy was noted in the serum. There was no evidence of myeloma in the bone marrow aspirate, scintigram or X-ray of the bone. A biopsy specimen of the kidney showed massive deposits of structureless material in the glomeruli. Marked cell infiltration was also observed in the interstitium. Multinucleated giant cells were occasionally seen in the Bowman's capsules and the interstitium. There were reactive changes in the Bowman's capsule adjacent to the giant cell. The deposits were proved to be amyloid by positive staining with Congo red and apple-green birefringence by polarized light. In addition, microfibrills seen on electron microscopy displayed deposits. Amyloid depositions were observed in other tissues such as gingiva, skin and tongue. Staining of amyloid with Congo red was resistant to potassium permanganate, and amyloid was positively stained with lambda-light chain of immunoglobulin. These findings indicated that the patient had primary amyloidosis. Infiltration of the multinucleated giant cell has been reported only in patients with familial amyloidosis and secondary amyloidosis associated with rheumatoid arthritis. To our knowledge the present case is a first report of the giant cell infiltration in a Bowman's capsule in primary amyloidosis.