Proliferative myositis: case report and review of the literature

Abstract

Proliferative myositis is a rre benign pseudosarcomatous inflammatory process that rapidly grows in muscles. Its clinical and radiological features may, however, simulate a malignant tumor. We report ultrasound and MRI appearances of a 63 years-old woman with no significant anterior pathological history presented to our radiology department with two weeks history of a painful mass in the left musculus latissimus dorsi, increasing progressively in size, without history of recent trauma. This study describes the imaging features of these pseudo inflammatory process, which may help to suggest the diagnosis, but the imaging finding are variable and nonspecific. However, histopathological examination is usually recommended to confirm the diagnosis. In our case, the final diagnosis was proved by ultrasound-guided biopsy. We also review the imaging features of this entity in the current literature.

Keywords: MRI; Proliferative myositis; Ultrasonography.

Fig. 1

Ultrasound appearance of proliferative myositis. Longitudinal ultrasound image demonstrated the heterogeneously echogenic mass with traversing continuous muscle fibers.

Fig. 2

MRI appearances of proliferative myositis. • Mass developed within the large musculus latissimus dorsi, presented with iso signal to the muscle on axial T1 weighted images (A), hypersignal on axial T2 weighted images (B). • The pattern of preserved continuous muscle fibers is a specific finding in PM more marked on coronal DP (C), and sagittal DP (D) with fat saturation. • The sequences after intravenous administration of gadolinium (E, F) showed homogeneous enhancement of the lesion.