[32] Interobserver Reliability in the Histopathological Diagnosis of Peripheral Cartilaginous Tumors in Patients with Multiple Osteochondromas: How Can We Improve Diagnostic Quality?

Carlos E de Andrea, Herman M Kroon, Ron Wolterbeek, Salvatore Romeo, Andrew E Rosenberg, Barry R DeYoung, Bernadette Liegl-Atzwanger, Carrie Y Inwards, Esther Hauben, Edward F McCarthy, Miguel Idoate, Nicholas A Athanasou, Kevin B Jones, Pancras CW Hogendoorn, Judith VMG Bovee. Leiden University Medical Center, Leiden, Netherlands; Treviso Regional Hospital, Treviso, Italy; Massachusetts General Hospital, Boston; University of Iowa Carver College of Medicine, Iowa City; Medical University of Graz, Graz, Austria; Mayo Clinic, Rochester; University Hospitals Leuven, Leuven, Belgium; Johns Hopkins Hospital and Johns Hopkins University School of Medicine, Baltimore; University of Navarra, Pamplona, Spain; University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom; University of Utah, Salt Lake City

Background: The distinction between benign and malignant peripheral cartilaginous tumors is a challenging subject in surgical pathology.
Design: The aim of this study was to investigate interobserver reliability in histological diagnosis of peripheral cartilaginous tumors in the setting of multiple osteochondromas and to evaluate the most common morphological parameters that characterize each tumor type. Interobserver reliability was assessed by 12 specialized bone-tumor pathologists in a set of 38 cases from patients with multiple osteochondromas.
Results: Substantial agreement in the histological diagnosis of peripheral cartilaginous tumors was observed (intraclass correlation coefficient = 0.78). Evaluation of morphological parameters (singly or collectively) among the concordant cases showed that well-known histological features for malignancy, such as nodularity, presence of binucleated cells, irregular calcification, cystic changes, and necrosis could not reliably distinguish osteochondroma from low-grade peripheral chondrosarcoma. The presence of nuclear pleomorphism and mitoses were useful parameters to differentiate low-grade from high-grade peripheral chondrosarcoma. With regard to cartilage cap thickness among the concordant cases, osteochondromas were significantly thinner than low- and high-grade secondary peripheral chondrosarcomas.
Conclusions: Our study shows that morphological parameters usually associated with malignancy cannot reliably predict neoplastic transformation of an osteochondroma in the setting of multiple osteochondromas and emphasize the importance of a multidisciplinary approach to diagnose peripheral cartilaginous tumors.
Category: Bone & Soft Tissue

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 9, Tuesday Morning


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