title: Periosteal fasciitis in a 7-year old girl: a diagnostic dilemma.
abstract: Periosteal fasciitis, considered a subtype of nodular fasciitis, is a rare benign soft tissue mass often misdiagnosed as a malignant lesion due to its fast and infiltrative growth pattern and histological features. Nodular fasciitis is usually found in the upper extremities in adults and in the head and neck region in children. Incorrect diagnosis may lead to overtreatment, potentially causing disturbed orofacial development in growing children. A rapidly growing asymptomatic mass, initially suspected to be a malignant bone tumour, was found in the left angle area of the mandible in a healthy 7-year-old girl. Radiographic examination revealed an exophytic, expansile and destructive nodule arising from the periosteal region. A diagnosis of periosteal fasciitis was established based on histological findings in an open biopsy specimen and the lesion was subsequently enucleated. Fluorescence in situ hybridization analysis revealed a USP6 gene rearrangement and confirmed the diagnosis molecularly. Due to the aggressive growth pattern without external trauma and the results of the gene rearrangement test, it is suggested that nodular fasciitis be regarded as a benign neoplasm rather than as a reactive process. The patient remains free of disease at 3 years after surgery.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Institute of Dentistry, University of Turku, Turku, Finland; Department of Oral and Maxillofacial Diseases, Turku University Hospital, Turku, Finland. Electronic address: mehela@utu.fi.
authors.forename: M
authors.initials: M
authors.lastname: Lääveri
authors.affiliation: Department of Oral and Maxillofacial Surgery, Institute of Dentistry, University of Turku, Turku, Finland; Department of Oral and Maxillofacial Diseases, Turku University Hospital, Turku, Finland; Department of Oral Diagnostic Sciences, Institute of Dentistry, University of Eastern Finland, and Department of Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Heikinheimo
authors.affiliation: Bone Tumour Reference Centre and DOESAK Reference Registry, Institute of Pathology, University Hospital Basel, Basel, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Baumhoer
authors.affiliation: Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Slootweg
authors.affiliation: Department of Oral and Maxillofacial Surgery, Institute of Dentistry, University of Turku, Turku, Finland; Department of Oral and Maxillofacial Diseases, Turku University Hospital, Turku, Finland.
authors.forename: R-P
authors.initials: RP
authors.lastname: Happonen
mesh_terms: D001706:Biopsy; D002648:Child; D003937:Diagnosis, Differential; D005208:Fasciitis / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008336:Mandibular Diseases / Q000473:pathology* / Q000601:surgery*; D010521:Periosteum / Q000473:pathology* / Q000601:surgery*
keywords: FISH; USP6 gene; jaw tumours; neoplasms of children; nodular fasciitis