Marco Gambarotti1, Angelo P Dei Tos1,2,3, Daniel Vanel1, Piero Picci1, Dino Gibertoni4, Michael J Klein5, Alberto Righi1. 1. Department of Pathology, IRCCS Rizzoli Orthopaedic Institute, Bologna, Italy. 2. Department of Pathology and Molecular Genetics, Treviso General Hospital, Treviso, Italy. 3. Department of Medicine, University of Padua, School of Medicine, Padua, Italy. 4. Unit of Hygiene, Public Health and Biostatistics, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy. 5. Department of Pathology and Laboratory Medicine, Hospital for Special Surgery, New York, NY, USA.
Abstract
AIMS: Osteoblastoma-like osteosarcoma is a rare variant of osteosarcoma (1% of all osteosarcomas), histologically similar to osteoblastoma. In the current World Health Organisation (WHO) classification, osteoblastoma-like osteosarcoma is classified within the group of conventional (high-grade) osteosarcomas. However, several published cases have been actually regarded as low-grade malignant tumours. As strict morphological criteria to distinguish between low- and high-grade lesions are not available, we reviewed our series of osteoblastoma-like osteosarcomas in the attempt to identify clinical and morphological features predictive of aggressiveness. METHODS AND RESULTS: We retrieved 15 cases of osteoblastoma-like osteosarcoma from the files of the Istituto Ortopedico Rizzoli. Patients received various treatments. Five patients developed metastasis and five patients developed local recurrences (all after incomplete surgery). Eleven patients were alive without disease, while four patients died of their disease. Statistical analysis revealed a statistically significant (P = 0.048) lower disease-free survival in patients with areas of conventional (high-grade) osteosarcoma. CONCLUSIONS: With the important limitation of a small cohort of patients, the presence of areas of conventional (high-grade) osteosarcoma is the only parameter to predict the aggressiveness of osteoblastoma-like osteosarcoma.
AIMS: Osteoblastoma-like osteosarcoma is a rare variant of osteosarcoma (1% of all osteosarcomas), histologically similar to osteoblastoma. In the current World Health Organisation (WHO) classification, osteoblastoma-like osteosarcoma is classified within the group of conventional (high-grade) osteosarcomas. However, several published cases have been actually regarded as low-grade malignant tumours. As strict morphological criteria to distinguish between low- and high-grade lesions are not available, we reviewed our series of osteoblastoma-like osteosarcomas in the attempt to identify clinical and morphological features predictive of aggressiveness. METHODS AND RESULTS: We retrieved 15 cases of osteoblastoma-like osteosarcoma from the files of the Istituto Ortopedico Rizzoli. Patients received various treatments. Five patients developed metastasis and five patients developed local recurrences (all after incomplete surgery). Eleven patients were alive without disease, while four patients died of their disease. Statistical analysis revealed a statistically significant (P = 0.048) lower disease-free survival in patients with areas of conventional (high-grade) osteosarcoma. CONCLUSIONS: With the important limitation of a small cohort of patients, the presence of areas of conventional (high-grade) osteosarcoma is the only parameter to predict the aggressiveness of osteoblastoma-like osteosarcoma.
Authors: Kivilcim Eren Erdogan; Marina Pacheco; Marco Gambarotti; Giovanna Magagnoli; Marta Sbaraglia; Tommaso Frisoni; Alberto Righi; Angelo Paolo Dei Tos Journal: Virchows Arch Date: 2021-01-28 Impact factor: 4.064