The kidney disease of Crow-Fukase (POEMS) syndrome: a clinico-pathological study of four cases.

We studied four cases of Crow-Fukase syndrome with renal dysfunction. Kidney specimens obtained by needle biopsy showed glomerular lesions resembling those seen in conditions characterized by microangiopathy. Common glomerular findings by light microscopy were mesangial expansion and narrowing of the capillary lumina. An enlarged subendothelial space and mesangial area with deposition of amorphous material as well as swelling and vacuolization of endothelial cells were observed by electron microscopy. In an active phase, severe mesangial edema and segmental mesangiolysis, and in a late stage, mesangial cell interposition and sclerosis were seen. Tests by immunofluorescence microscopy for the presence of immunoglobulins A, M, G, lambda and kappa light chains, C3, and C4 were negative. Decay accelerating factor was found in glomeruli and in the vascular pole. Other findings included lymph node angiosclerosis, peripheral nerve microangiopathy and hemangioma formation with endothelial cell proliferation. These observations suggest that chronic endothelial injury constitutes the basic pathology of Crow-Fukase syndrome. Hemodialysis was required to manage anasarca in three of the patients although serum creatinine levels were below 5.0 mg/dl. Urinalysis revealed mild abnormalities and did not reflect the severity of the glomerular lesion. Corticosteroids given to three of the patients were effective in controlling fever and the lymphadenopathy; in two cases the corticosteroids induced a recovery of renal function. Thus Crow-Fukase syndrome may be due to chronic endothelial injury; the clinical symptoms and renal involvement respond to corticosteroid therapy.