Membranous nephropathy and Kimura's disease manifesting a hip mass. A case report with literature review.

We report a case of Kimura's disease with membranous nephropathy. A 15-year-old Japanese boy was referred to our hospital with proteinuria and a subcutaneous mass in the hip. Renal biopsy demonstrated secondary membranous nephropathy (MN) with mild mesangial proliferation and some electron-dense deposits in the mesangium. Laboratory tests revealed eosinophilia and a high level of serum IgE, which are common findings in Kimura's disease. A biopsy of the mass in the hip was performed and Kimura's disease was diagnosed. Treatment with oral prednisolone resulted in a decrease of proteinuria and regression of the subcutaneous mass. Kimura's disease should be included in the differential diagnosis of secondary MN.