Hyperthermic isolated limb perfusion with tumor necrosis factor-α and melphalan in advanced soft-tissue sarcomas:: Histopathological considerations

Background: Hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan was used as induction treatment in locally advanced extremity soft-tissue sarcomas for limb sparing surgery. The typical histopathological changes that occur in these tumoral masses are described in a series of 30 patients. Methods: Fresh tumor specimens of 27 high grade extensive soft-tissue sarcomas and 3 recurrent desmoid tumors of the extremities were collected 6 to 8 weeks after hyperthermic isolated limb perfusion with tumor necrosis factor-alpha plus melphalan. The specimens were studied for surgical margins, extent and type of tumor necrosis, lymph node involvement, perineural and vascular invasion, and the effects on adjacent normal tissues such as nerves, muscles, and blood vessels. Results: The typical histological changes were central cystic hemorrhagic necrosis with pericystic extensive fibrosis. Some nonspecific changes were noted in the soft tissues around the mass. In eight cases, more than 90% necrosis was found. In 17 cases, the extent of necrosis ranged between 60% and 90% (80%-90% in 4 of 17 cases). In five cases, less than 60% necrosis was noted. The best responses (>90% necrosis) were observed in distally located tumors. The responsive types were malignant fibrous histiocytoma, followed by myxoid liposarcoma and synovial sarcoma. Desmoid tumors showed less necrosis than high grade sarcomas. Vascular invasion was observed in two cases and intralesional venous thrombosis in one case. No perineural invasion or lymph nodes involvement were observed. The soft tissues adjacent to the tumor bed did not show major morphological changes. No correlation was found between the histological changes and each of the following: the anatomical (upper vs. lower limb) or compartmental location of the tumor; whether the tumor was primary or recurrent; and the types of previous treatment (systemic chemotherapy or radiotherapy) and tumor size. Conclusions: This is the first serial histological description of the effects of tumor necrosis factor-alpha and melphalan administered via hyperthermic isolated limb perfusion on the tumoral masses of limb soft-tissue sarcomas. The small number of specimens and, especially, the variability of tumors preclude definite conclusions. Larger numbers and more homogeneity are needed in future studies.