title: Florid reactive periostitis of the long bone: A case series of seven patients.
abstract: BACKGROUND
  Florid reactive periostitis (FRP) is a rare benign periosteal lesion, which mostly involves the tubular bones of the extremities. FRP of the long bone is especially rare. We here report a case series of long bone FRP and also discuss the differential diagnosis and clinical outcome of our series.
  
  
  METHODS
  In total, four female and three male patients with long bone FRP and a mean age of 25.1 years were evaluated for this study, from which four upper extremity and three lower extremity FRP lesions were identified. Patients were classified according to the clinical, radiological and pathological manifestations of the lesion.
  
  
  RESULTS
  Periosteal reaction and edema around the lesions were observed in all cases. Calcified mass, bone marrow edema and cortical erosion were observed in six out of seven patients. Moreover, two lesions with peripheral mineralization and zoning appearances were observed. Limb rest and anti-inflammatory therapy proved to be sufficient treatment in all cases. The lesions were spontaneously resolved in all cases, leaving a residual exostosis.
  
  
  CONCLUSIONS
  Our report indicates that short bone and long bone FRP could reveal different characteristics in some aspects, including the choice of the therapeutic approach. In spite of the favorable clinical outcome of long bone FRP, its differentiation from more aggressive lesions, especially osteosarcoma and osteomyelitis, should still be taken into consideration. In addition, according to our evidence, the implication of the zonal pattern in differential diagnosis of FRP and myositis ossificans (MO) could be re-evaluated.
authors.affiliation: Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Khodamorad
authors.initials: K
authors.lastname: Jamshidi
authors.affiliation: Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Behrooz
authors.initials: B
authors.lastname: Givehchian
authors.affiliation: Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. Electronic address: mirzaeialireza26@gmail.com.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mirzaei
mesh_terms: D000293:Adolescent; D000328:Adult; D062005:Biopsy, Large-Core Needle; D001859:Bone Neoplasms / Q000150:complications* / Q000175:diagnosis; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015831:Osteochondroma / Q000150:complications* / Q000175:diagnosis; D010522:Periostitis / Q000175:diagnosis* / Q000209:etiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult