Chondroblastoma-like Osteosarcoma.

CONTEXT.—: Chondroblastoma-like osteosarcoma is an exceedingly rare variant of osteosarcoma, with 22 cases reported in the English-language literature. The tumor is slightly more common in males, with a broad age range (from childhood to elderly). The most commonly involved bones are the metatarsus and tibia, followed by the femur. Most tumors have malignant or worrisome radiographic findings. Prognosis is variable, depending on the presence or absence of lung metastases, local recurrence, and probably tumor location. Histologically, chondroblastoma-like osteosarcoma is characterized by monotonous, minimally to moderately atypical rounded cells with ovoid nuclei resembling chondroblastoma, and abnormal osteoid deposition with destruction of the bone.

OBJECTIVE.—: To review the clinical, radiographic, and histopathologic features of chondroblastoma-like osteosarcoma.

DATA SOURCES.—: PubMed-published chondroblastoma-like osteosarcoma cases in the English-language literature.

CONCLUSIONS.—: Although exceedingly rare, chondroblastoma-like osteosarcoma should be considered in the differential diagnosis of chondroblastoma, especially in the presence of radiologic findings suggestive of an aggressive lesion.