Results of diagnostic review in pediatric bone tumors and tumorlike lesions.

Background: Histological examination of bone tumors is one of the most difficult subjects in pathology. In this manuscript, correctness of initial histological diagnosis in pediatric bone tumors and tumorlike lesions was investigated.

Procedure: All 262 bone tumor specimens of children up to the age of 19 years reviewed from 1999 to 2003 by the Netherlands Committee on Bone Tumors were included. Initial diagnosis and diagnosis after review were compared.

Results: Only 60% of original diagnoses proved to be correct. After classification according to the main categories of the World Health Organization classification, only 75% of tumors were correctly categorized. Thirteen of the 60 malignant tumors were not recognized as malignant. Seven of 198 benign lesions were reclassified as malignant. Kappa values were indicative for good agreement in the (by the Ministry of Health designated) bone tumor centers. For nondesignated hospital kappa values, a substantial lower level of agreement was noted. Agreement was almost perfect in Ewing/primitive neuroectodermal tumors. For cartilaginous, osteogenic, and fibrous tumors, agreement was lower. Adamantinomas were not recognized in non-bone tumor centers. For the remaining group composed of miscellaneous tumors, poor levels of agreement were noted.

Conclusions: We conclude that correct diagnosis of childhood bone tumors requires review by a multidisciplinary team of experts. Specifically in non-bone tumor centers, the correctness of the initial diagnosis can be questioned.