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. Introduction Nodular fasciitis (NF) is a benign and quasi-neoplastic proliferation of fibroblasts that shows a rapid growth [1]. We describe a case of intramuscular NF that is rare when it occurs in the shoulder and that is probably induced by repeated local injections. Case Report A 44-year-old man complained of a severe painful mass in the right shoulder after having felt discomfort in the shoulder for one month. For several months previously, this patient had been treated for bicipital tenosynovitis in that shoulder with rehabilitation and trigger point injection therapies using as corticosteroids, local anesthetics, and/or nonsteroidal anti-inflammatory drugs. The occurrence of the lesion or mass was exactly where those drugs had been injected. Magnetic resonance (MR) images disclosed a mass in the anterior fibers of the deltoid muscle that appeared to be isointense to skeletal muscle on T1-weighted and hyperintense to fat on T2*-weighted MR images (Fig. 1AB).
展开▼
