Metastatic chondroblastoma. Report of a fatal case with a review of the literature on atypical, aggressive, and malignant chondroblastoma

A boy with metastatic and fatal chondroblastoma is presented. Unlike previously published examples of metastatic chondroblastoma, these metastases developed before any operative manipulation of the primary tumor. The histologic characteristics of the primary, metastatic, and locally recurrent tumors were those of a conventional chondroblastoma. A review of published cases of atypical, aggressive, and malignant chondroblastoma is presented with current follow-up information. Although some metastatic chondroblastomas may result from operative manipulation of the primary tumor and are clinically benign, other histologically benign chondroblastomas exist that are capable of pursuing a malignant course. The authors designate these as malignant chondroblastomas. No histologic criteria exist for the separation of these tumors.