Membranous nephropathy associated with angiomatoid fibrous histiocytoma in a pediatric patient.

BACKGROUND: Though membranous nephropathy is a much more common cause of nephrotic syndrome in the adult population, it accounts for only a small fraction of cases in pediatrics. CASE-DIAGNOSIS/TREATMENT: We report a case of a 16-year-old boy with nephrotic syndrome due to membranous nephropathy in the setting of a rare tumor, angiomatoid fibrous histiocytoma. This patient's nephrotic-range proteinuria completely resolved following resection of this tumor. Angiomatoid fibrous histiocytoma, while known to cause other paraneoplastic syndromes such as anemia, has never been reported to cause membranous nephropathy.
CONCLUSIONS: This case highlights a novel and treatable secondary cause of membranous nephropathy. Because secondary causes are more common in children than in adults, a high index of suspicion for other underlying pathology including malignancy should be considered. It also suggests that urinalysis may be a helpful screening tool in cases of angiomatoid fibrous histiocytoma.