Sarcomes des tissus mous des extrémités. Rôle de l'imagerie dans la prise en charge initiale

Extremities Soft Tissue Sarcomas, more Common and as Dangerous as Bone Sarcomas

Musculoskeletal sarcomas are rare diseases that require attention. They often present high degree of malignancy at diagnosis and, if underestimated, they can evolve aggressively locally and systemically. They present as soft tissue sarcoma and bone sarcomas, with soft tissue being four to five times more common. Most soft tissue sarcomas occur in the extremities. The most common subtypes in children and adolescents are rhabdomyosarcoma and synovial sarcoma; in adults, undifferentiated pleomorphic sarcoma, liposarcoma, leiomyosarcoma, myxofibrosarcoma and synovial sarcoma; all with a high degree of histological malignancy. Many soft tissue sarcomas are confused with benign soft tissue tumors, 100 times more common, so they are resected without the necessary planning, resulting in amputation of a limb that could have been preserved. As in all cancers, the most important prognostic factor is metastatic disease. When it is present, the overall survival rate falls around 20 to 30%. Survival rates are generally similar between bone and soft tissue sarcomas. So soft tissue sarcomas, in addition to being more prevalent, are as aggressive as bone sarcomas, deserving a lot of attention from orthopedic surgeons, who are often the first line of care of carriers of these tumors.

Diagnostic value of delineating deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3.0 T magnetic resonance imaging

PURPOSE

To determine the association between morphological changes to the deep fascia and the malignancy of soft-tissue tumors in the lower limbs using 3.0 T magnetic resonance imaging (MRI).

MATERIALS AND METHODS

MR images of 47 consecutive patients with 48 pathologically proven soft-tissue tumors in the lower limbs were retrospectively reviewed by two radiologists. Lesions were divided into four groups according to their predominant location relative to the deep fascia: Group A: subcutaneous lesions superficial to the deep fascia (n = 9); Group B: lesions located beneath the deep fascia (n = 8); Group C: lesions centered in the interspaces of the deep fascia investment (n = 11); and Group D: intramuscular lesions (n = 20).

RESULTS

The deep fascial structures were complete in all of the 19 benign lesions. In malignant lesions, destruction signs of the deep fascia were observed in 27 of the 29, which were characterized by disappearance/disruption of the fascial line and aggressive growth penetrating through the fascial line into the adjacent compartment, or disappearance/disruption of the intermuscular septa and embedding the mutilated fascial septa within the lesion, or destruction of the fascia-muscle planes and abolishment of the deep fascial interspaces. Diagnosis of malignancy based on the signs of destruction of the deep fascial structure delineated with 3.0 T MRI, the sensitivity, specificity, and accuracy were 93.10%, 100%, and 95.83%, respectively.

CONCLUSION

Tumor involvement and destruction of the deep fascial structures visualized by 3.0 T MRI may be of utility in differentiating malignant from benign soft-tissue tumors.