title: Focal Inflammatory Myositis on 18F-FDG PET/CT.
abstract: Focal myositis is a rare benign inflammatory pseudotumor that can mimic malignancy, clinically and on imaging. A 34-year-old man presented with a 3-week history of sudden-onset, nontender, left upper neck mass that was nonresolving with antibiotics. Anatomical imaging was concerning for a sarcoma of the sternocleidomastoid muscle with possible regional nodal metastases and surrounding inflammatory change. F-FDG PET/CT showed marked FDG uptake extending around the anterior border of the sternocleidomastoid muscle with no FDG-avid local nodal disease. Core biopsy of the sternocleidomastoid muscle and adjacent node revealed inflammatory changes. A diagnosis of focal inflammatory myositis was made.
authors.affiliation: From the *Specialised PET Services Queensland; and Departments of †Nuclear Medicine, and ‡Ear, Nose, and Throat Surgery, Royal Brisbane & Women's Hospital, Herston, Queensland, Australia.
authors.forename: Olivia
authors.initials: O
authors.lastname: Bennett
authors.forename: Aravind S
authors.initials: AS
authors.lastname: Ravi Kumar
authors.forename: Julie
authors.initials: J
authors.lastname: Agnew
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D009220:Myositis / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography; D019275:Radiopharmaceuticals; D012509:Sarcoma / Q000000981:diagnostic imaging*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18