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. (C) 2011 Wiley Periodicals, Inc. J Clin Ultrasound 39: 135-140, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/jcu.20792