Post traumatic myositis ossificans: Sonographic findings

Purpose: The aim of this paper is to describe the sonographic (US) features of post traumatic myositis ossificans (PTMO). Methods: Fifteen patients with histopathological diagnosis of PTMO were included. The following US parameters were evaluated: presence of a mass, calcifications, power Doppler signals, and relationship with adjacent structures. Results: Five patients (33.3%) were diagnosed as early PTMO and 10 (66.6%) as mature PTMO. In both early and mature PTMO, US showed an oval hypoechoic mass, without infiltrative borders, located in a muscular belly. In the early phase, a center of less echogenicity was observed, associated with an outer sheet-like hyperechoic peripheral rim, while, in the mature phase, peripheral calcification created more reflections and distal acoustic shadowing was observed. Conclusions: US is highly sensitive in the detection of PTMO, helps differentiate between PTMO and malignant soft tissue tumors, and can be used for follow-up of the lesions.