Membranous glomerulonephritis with superimposed ANCA-associated vasculitis: another case report.

Dear Sir,

We report here another case of primitive membranous nephritis with superimposed anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, in addition to 10 cases recently reported by Nasr et al. [1]. This association has since been reported in relation with systemic lupus erythematosus, hepatitis B or C virus infection and treatment with penicillamine, hydralazine and propylthiouracil [2-5].

A 67-year-old Caucasian male was presented at the emergency department with anorexia, nausea and vomiting. Routine laboratory tests revealed severe renal failure and a consultation with a nephrologist was requested. Blood pressure was 170/100 mm Hg, and urine output over 24 h was 2.2 L. Medical history was remarkable for hypertension (in treatment with β-blockers) and possible upper respiratory infection about 4 weeks before admission (treated with amoxicillin 2 g/day orally). Urinalysis revealed haematuria (+++) and non-selective proteinuria (4.8 g/24 h), in front of seric albumin levels of 2.6 g/dL. Skin examination revealed no significant lesions.

LAC, ANA, anti-DNA, ENA, HBsAg, anti-HCV, cryoglobulins, complement levels, ANCAs and serum protein electrophoresis were normal. Perinuclear ANCA was positive at 1:40.

A renal biopsy was performed, and sampling for LM included 11 glomeruli, three of which were globally sclerotic. Light microscopy revealed the presence of extracapillary proliferation which compressed the glomerular tuft and vasculitis with fibrinoid necrosis of the arterial wall. Cellular crescents were present exclusively in three glomeruli. The crescents were accompanied by foci of fibrinoid necrosis with endocapillary and extracapillary fibrin. Tubular atrophy and interstitial fibrosis were absent. Interstitial inflammation was present, focal and accompanied by tubular degenerative changes. There was evidence of necrotizing vasculitis. IF revealed granular, segmental to global glomerular capillary wall positivity for IgG, kappa and lambda. Weaker staining for C3 was detected. Staining for fibrinogen highlighted areas of glomerular fibrinoid necrosis. Immunofluorescence shows intense staining of the arterial wall for IgG.

The final diagnosis was ‘membranous glomerulonephritis with superimposed ANCA-associated vasculitis and extracapillary proliferation’. The patient started a 6-month course of methylprednisolone (1 g i.v.) for three consecutive days at months 1, 3 and 5, followed by methylprednisolone per os alternated with cyclophosphamide per os. The patient is in partial remission. Creatinine fell to 1.6 mg/dL while proteinuria reduced to 1.2 g/24 h. Treatment ended on September 2010.

Conflict of interest statement. None declared.