Remission of secondary membranous nephropathy in a patient with Kimura disease after surgical resection

Kimura disease (KD) is an eosinophilic, granulomatous, benign, chronic inflammatory disease with an unknown etiology. A 33-year-old woman visited our hospital because of a palpable, left subclavian mass, a left scapulo-anterior pseudoaneurysm, and nephrotic syndrome. Her subclavian lymph node biopsy examination result was consistent with KD, and results of a renal biopsy indicated secondary membranous nephropathy. After renal histological examination confirmed nephropathy, treatment with prednisolone and cyclosporine was initiated, which was maintained for over 1 year. However, this therapy only provided a transient improvement in proteinuria. One year after commencing the treatment, both proteinuria and azotemia aggravated as the left axillary mass doubled in size. Finally, the mass was surgically excised, following which the azotemia rapidly normalized and proteinuria resolved within 1 month. This case shows that tumor resection in a patient with KD with secondary nephropathy may resolve secondary renal manifestations. Furthermore, reversible renal dysfunction may be caused by unknown secreted molecules.