title: Primary osteosarcoma of the breast after complete resection of a metaplastic ossification: a case report.
abstract: BACKGROUND
  Primary osteosarcoma of the breast is an extremely rare lesion. The pathogenesis of primary osteosarcomas is controversial.
  
  
  METHODS
  We present the case of a 63-year-old white German woman who presented with a mass in her right breast after routine screening. The core needle biopsy showed ductal hyperplasia with metaplastic ossification of the breast tissue. Complete excision of the lesion with standard safety margins was performed. The final diagnosis was metaplastic ossification. Three years later, our patient presented again with a painless lump in her right breast about 15 × 8 × 7 cm, extending to the lower part of axilla with skin ulceration. Pathologic diagnosis was osteosarcoma. Positron emission tomography and computed tomography and staging showed no other lesions. Modified radical mastectomy and axillary lymph node dissection was performed, no lymph node metastases were found.
  
  
  CONCLUSIONS
  Our case highlights the possibility that primary osteosarcoma of the breast may develop after complete resection with the classical safety margin for metaplastic ossification. Long-term follow-up after resection of this benign breast lesion is required.
authors.affiliation: Department of Pathology, Ludmillenstift hospital, Meppen, Germany.
authors.forename: Evariste
authors.initials: E
authors.lastname: Gafumbegete
authors.affiliation: Department of gynecology and obstetrics, Ludmillenstift hospital, Meppen, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Fahl
authors.affiliation: Clinic of Emsland-gynecology, Lingen, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Weinhardt
authors.affiliation: Clinic of pathology, Vechta, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Respondek
authors.affiliation: Neurosurgery Teaching Program, Faculty of Medicine, University of Traditional Medicine, Yerevan, Armenia. alaa.elsharkawy@googlemail.com.
authors.forename: Alaa Eldin
authors.initials: AE
authors.lastname: Elsharkawy
mesh_terms: D001365:Axilla / Q000473:pathology*; D044963:Biopsy, Fine-Needle; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D015411:Mastectomy, Modified Radical / Q000379:methods*; D008875:Middle Aged; D012516:Osteosarcoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
keywords: Ductal hyperplasia; Metaplastic ossification; Primary osteosarcoma