title: Do primary mammary osteosarcoma and chondrosarcoma exist? A review of a large multi-institutional series of malignant matrix-producing breast tumours.
abstract: The existing literature describing the clinicopathological features and behaviour of matrix-producing (MP) malignant breast tumours presents conflicting results. As a consequence it remains uncertain whether these tumours should be treated as sarcoma and managed by a specialist sarcoma team or treated using the same principles as conventional ductal carcinoma, a dilemma that prompted this study. Improved understanding of the clinicopathological characteristics of primary mammary MP-sarcomas, namely osteosarcoma and chondrosarcoma, is required.
  
  
  METHODS
  In this large international multicenter series of malignant MP-tumours of the breast (no = 101) with follow-up information has been assessed and their outcome is compared to other subtypes of metaplastic breast carcinoma (MBC) (no = 253) and to grade, lymph node and hormone receptor-matched ductal breast carcinomas (no = 258).
  
  
  RESULTS
  The majority of MP-cancers were associated with epithelial features, which supports the concept that the majority of, if not almost all, primary MP breast sarcomas are of epithelial in origin (MBC). 21% showed nodal metastasis and the distribution of distant metastases resembled conventional mammary carcinoma. The prognosis of MP-MBC is comparable to matched ductal breast carcinoma and slightly better than other subtypes of MBC. Advanced stage (T3&T4) and development of recurrences were predictors of shorter survival in MP-MBC while grade and vascular invasion were not.
  
  
  CONCLUSIONS
  Most malignant MP breast tumours are variants of MBC. MP-MBC with predominant mesenchymal components behaves similar to ductal carcinomas and although data on their response to systemic therapy is limited, there is no evidence that they should be managed differently from other forms of triple negative breast cancer.
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust, and The University of Nottingham, Nottingham City Hospital Campus, Hucknall Road, Nottingham NG5 1PB, UK. emadrakha@yahoo.com
authors.forename: Emad A
authors.initials: EA
authors.lastname: Rakha
authors.forename: Puay Hoon
authors.initials: PH
authors.lastname: Tan
authors.forename: Abeer
authors.initials: A
authors.lastname: Shaaban
authors.forename: Gary M
authors.initials: GM
authors.lastname: Tse
authors.forename: Fina Climent
authors.initials: FC
authors.lastname: Esteller
authors.forename: Carolien H M
authors.initials: CH
authors.lastname: van Deurzen
authors.forename: Dave
authors.initials: D
authors.lastname: Purnell
authors.forename: Anne
authors.initials: A
authors.lastname: Stotter
authors.forename: Timothy
authors.initials: T
authors.lastname: Chan
authors.forename: Rin
authors.initials: R
authors.lastname: Yamaguchi
authors.forename: David
authors.initials: D
authors.lastname: Dodwell
authors.forename: Agnes
authors.initials: A
authors.lastname: Jager
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Soler
authors.forename: Enaam
authors.initials: E
authors.lastname: Juneinah
authors.forename: M L
authors.initials: ML
authors.lastname: Plaza
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Hodi
authors.forename: Tom
authors.initials: T
authors.lastname: McCulloch
authors.forename: Andrew H S
authors.initials: AH
authors.lastname: Lee
authors.forename: Ian O
authors.initials: IO
authors.lastname: Ellis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D002813:Chondrosarcoma / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008679:Metaplasia; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D012516:Osteosarcoma / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D011379:Prognosis; D016019:Survival Analysis