title: Noninfectious painful neck mass mimicking malignancy in a child.
abstract: BACKGROUND
  A large painful mass on the posterior neck of a child of a relatively short duration is uncommon. Barring infectious origin, differential diagnosis can be difficult without a definitive biopsy.
  
  
  RESULTS
  A 12-year-old girl had a markedly painful posterior neck mass and limitation of neck motion without fever for 1 month. The rapid clinical course and poorly defined marginal zone of the CT images led to suspicion of malignancy. Although the initial frozen section suggested low-grade fibrosarcoma, a successful wide excision and paraffin pathology confirmed the diagnosis of myositis ossificans circumscripta (MOC) from the semispinalis capitis muscle.
  
  
  CONCLUSIONS
  The occurrence of MOC in children is rare and may easily be misdiagnosed as soft tissue sarcoma. Both knowledge of the disease and guidelines for taking an aggressive biopsy sample are essential for correct diagnosis and appropriate treatment.
authors.affiliation: Department of Otolaryngology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Tse-Yi
authors.initials: TY
authors.lastname: Lin
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Wu
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Chiang
authors.forename: Wen-Rei
authors.initials: WR
authors.lastname: Kuo
authors.forename: Kuen-Yao
authors.initials: KY
authors.lastname: Ho
authors.forename: Ka-Wo
authors.initials: KW
authors.lastname: Lee
mesh_terms: D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D005354:Fibrosarcoma / Q000175:diagnosis; D006258:Head and Neck Neoplasms / Q000175:diagnosis; D006801:Humans; D009221:Myositis Ossificans / Q000175:diagnosis* / Q000601:surgery; D009334:Neck Muscles / Q000601:surgery