An unresectable retroperitoneal malignant fibrous histiocytoma: A case report

Malignant fibrous histiocytoma (MFH) is most commonly observed in the extremities and the trunk but rarely in retroperitoneum. The present case report documents a 64‑year‑old man who was admitted with an abdominal palpable mass for 6 months. After a thorough investigation, a tumor of the retroperitoneum was identified adhered to adjacent organs and vessels. The patient experienced mild hydronephrosis and hydroureter as a result of the tumor compression. A number of previous surgeons considered the tumor unresectable and suggested palliative treatment. En bloc resection of the tumor was attempted but incomplete surgery was performed initially as the tumor was friable and prone to bleeding. Therefore, a biopsy of the tumor was performed and a double J ureteral stent was set for hydronephrosis. Histopathological examination confirmed the tumor was an MFH. The patient received neo‑adjuvant chemotherapy with 4 cycles of mesna, doxorubicin, ifosfamide, and dacarbazine (MAID). A computed tomography scan demonstrated that the tumor had reduced in size following chemotherapy. En bloc resection of the tumor was arranged again 6 months later. The tumor exhibited a complete response to neo‑adjuvant chemotherapy after the formal pathological evaluation. The patient survives without tumor recurrence >5 years without recurrence.