Recklinghausen’s Neurofibromatosis Associated with Membranous Nephropathy

Yutaka Kobayashi, MD, Department of Medicine, School of Medicine, Kitasato University, 1-15-1, Kitasato, Sagamihara 228 (Japan) Dear Sir, We present here a rare case of Recklinghausen’s neurofibromatosis associated with membranous nephropathy. A detailed evaluation of the clinicopathological findings is described. A 68-year-old Japanese woman was admitted to Kitasato Universitiy Hospital on May 30,1990, because of general edema and severe proteinuria. She had a history of Recklinghausen’s neurofibromatosis since 1964. Her proteinuria was first pointed out in April 1989 and continued since then. In December 1989, general edema developed. On admission, physical examination revealed a blood pressure of 140/80 mm Hg and general edema. There were multiple subcutaneous neurofibromas covering the entire skin surface involving cafe au lait spots on the right knee and the axilla. Laboratory findings were as follows: urinary protein 3-4 g/day, sediment RBC negative, WBC count 6,900/μl with normal differentials, RBC count 351 × lOVμl, hemoglobin 10.6 g/dl, platelets 31.3 × lOVμl, ESR 59 mm/h, serum total protein 4.7 g/dl, albumin 3.1 g/dl, total cholesterol 404 mg/dl, urea nitrogen 22 mg/dl, crea-tinine 0.8 mg/dl, IgG 380 mg/dl, IgA 77 mg/ dl, IgM 131 mg/dl, CH50 33 U/ml, C3 56 mg/ dl, C415 mg/dl, ANA negative, RAtest negative, circulating immune complexes negative, Hbs-antigen negative, syphilis reaction negative, Ccr 62 1/day. Malignanacy survey revealed no abnormality. Renal biopsy was performed on the 21st hospital day. The histological findings were compatible with membranous nephropathy. The biopsy specimen contained 10 glomeruli showing a diffuse moderate thickening of the capillary walls. Silver impregnation revealed diffuse vacuolization of the capillary walls and the presence of perpendicular projections extending from the basement membrane. Significant cellular proliferations were unremarkable. Two of the glomeruli showed segmental sclerotic changes with some foam cells. Tubular degeneration and atrophy were focally observed. Interstitial fibrosis and mononuclear cell infiltration were also noted in some parts. Interstitial foam cells were also seen. Ultrastructurally, diffuse subepithelial and intramembranous dense deposits were observed. The glomerular basement membrane was thickened with wide spike formation and included intramembranous lucent deposits in some parts. Newly formed glomerular basement membrane materials were also seen. Subendothelial and mesangial dense deposits were not observed at all. Im-munohistochemically, IgG and C3