Malignant fibrous histiocytoma arising from a hydronephrotic kidney: a case report and review of the literature

Primary malignant fibrous histiocytoma (MFH) is extremely rare, and MFH arising from a hydronephrotic kidney has not been reported. When MFH originates from a long-standing hydronephrotic kidney, the imaging findings can include nearly invisible renal parenchyma and atrophy of the ureter and renal artery, in addition to the findings attributable to the MFH, and the MFH with hydronephrosis may be confused with a cystic renal cell carcinoma.