Does pre-operative MRI predict the risk of local recurrence in primary myxofibrosarcoma of the extremities?

Objective: The aim of this retrospective study is to analyze and classify magnetic resonance imaging (MRI) features of primary myxofibrosarcoma (MFS) of the extremities and their correlation with patients’ prognosis (local recurrence [LR] and sarcoma-specific survival [OS]). Methods: Ninety-four patients with primary MFS of the extremities were included. All MRI were performed with 1.5 Tesla magnet using a standard protocol. The presence of a “tail pattern” was recorded. Myxoid tumor component and contrast enhancement of the tumor were evaluated and graded with semiquantitative method using a newly proposed classification. Results: A tail-like pattern was observed in 32% MFS; most of the tumors presented with high myxoid features and high grade of gadolinium (Gd) enhancement. Type 3 myxoid characteristics (P = 0.003) were most often observed in FNCLCC grade 3 tumors. Estimated LR-free survival rate was 70.3% at 3 and 58.4% at 5 years. A higher LR-rate was observed in those tumors presenting a tail-like pattern at MRI (P = 0.039), in those with myxoid features type 2 and 3 (0.047) and in those with Gd enhancement grade 2 or 3 (P = 0.029). A worse OS was observed in Gd enhancement grade 3 (P = 0.013) and in deep tumors (P = 0.031). Conclusions: MFS features on preoperative MRI can be useful in order to identify risk classes of LR and OS. These data may suggest that patients with a tail-like pattern, high Gd enhancement and high myxoid features should be followed up more carefully after surgery.