Intramuscular Nodular Fasciitis in the Shoulder Probably Induced by Local Injections

We present herein a case of nodular fasciitis, intramuscular type, in the shoulder. A 44-year-old male complained of a hard mass in the anterior fibers of the deltoid muscle, where the lesion was isointense to skeletal muscle on T1-weighted and hyperintense to fat on T2*-weighted MR images. This lesion, histologically and immunohistochemically confirmed as a nodular fasciitis of intramuscular type by an incisional biopsy, was excised in a simple procedure three months later. We hypothesized that repeated injections for bicipital tenosynovitis had triggered the occurrence of nodular fasciitis in this case.