title: Interobserver reliability in the histopathological diagnosis of cartilaginous tumors in patients with multiple osteochondromas.
abstract: The distinction between benign and malignant cartilaginous tumors located peripherally in the bone may be a challenging task in surgical pathology. The aim of this study was to investigate interobserver reliability in histological diagnosis of cartilaginous tumors in the setting of multiple osteochondromas and to evaluate possible histological parameters that could differentiate among osteochondroma, low- and high-grade secondary peripheral chondrosarcoma. Interobserver reliability was assessed by 12 specialized bone-tumor pathologists in a set of 38 cases. Substantial agreement on diagnosis among all the reviewers was observed (intraclass correlation coefficient=0.78). Our study confirmed that mitotic figures and nuclear pleomorphism are hallmarks of high-grade secondary peripheral chondrosarcoma. However, despite the substantial agreement, we demonstrated that histology alone cannot distinguish osteochondroma from low-grade secondary peripheral chondrosarcoma in the setting of multiple osteochondromas, as nodularity, the presence of binucleated cells, irregular calcification, cystic/mucoid changes and necrosis were not helpful to indicate malignant transformation of an osteochondroma. On the other hand, among the concordant cases, the cartilage cap in osteochondroma was significantly less thicker than in low- and high-grade secondary peripheral chondrosarcoma. Therefore, our study showed that a multidisciplinary approach integrating clinical and radiographical features and the size of the cartilaginous cap in combination with a histological assessment are crucial to the diagnosis of cartilaginous tumors.
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: de Andrea
authors.forename: Herman M
authors.initials: HM
authors.lastname: Kroon
authors.forename: Ron
authors.initials: R
authors.lastname: Wolterbeek
authors.forename: Salvatore
authors.initials: S
authors.lastname: Romeo
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Rosenberg
authors.forename: Barry R
authors.initials: BR
authors.lastname: De Young
authors.forename: Bernadette
authors.initials: B
authors.lastname: Liegl
authors.forename: Carrie Y
authors.initials: CY
authors.lastname: Inwards
authors.forename: Esther
authors.initials: E
authors.lastname: Hauben
authors.forename: Edward F
authors.initials: EF
authors.lastname: McCarthy
authors.forename: Miguel
authors.initials: M
authors.lastname: Idoate
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Athanasou
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Jones
authors.forename: Pancras Cw
authors.initials: PC
authors.lastname: Hogendoorn
authors.forename: Judith V M G
authors.initials: JV
authors.lastname: Bovée
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002356:Cartilage / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology; D002648:Child; D019902:Chondrocytes / Q000473:pathology*; D002813:Chondrosarcoma / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005097:Exostoses, Multiple Hereditary / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D015203:Reproducibility of Results; D055815:Young Adult