Reunião Oncologia Pediátrica

In the absence of a specific diagnostic marker that discriminates accurately between chondroblastic osteosarcoma and conventional chondrosarcoma, it is often difficult or impossible for pathologists to distinguish between these 2 tumor types by standard morphological analysis; chondroblastic osteosarcoma produces chondroid matrix as well as osteoid matrix, thus, in small biopsy samples, osteoid matrix (the hallmark of osteosarcoma) may simply not be present.

Until now, when faced with an equivocal diagnosis, a pluridisciplinary discussion between surgeons, radiologists, oncologists, and pathologists resulted in the proposal of one of 3 clinical options to the patient.

1- The first was a second biopsy to increase the chance of detecting osteoid in the tumor, with the risk that even a new biopsy might miss any osteoid matrix.

2- The second option, usually proposed systematically in cases of patients younger than 25 years in which the probability of chondroblastic osteosarcoma is highest, was systemic neoadjuvant chemotherapy. This alternative is dangerous because of the toxicity of chemotherapy treatment to the blood, heart muscle, kidneys, and hearing, as well as consequences of sterility and even death for young patients. On the other hand, if chondroblastic osteosarcoma is not treated with neoadjuvant chemotherapy the prognosis is worsened.

3- Finally, a third clinical option would be to propose a radical surgery and a neoadjuvant therapy complement only if chondroblastic osteosarcoma were diagnosed after examination of the total bone specimen. This option is also dangerous because this patient, who did not receive chemotherapy at the beginning of the treatment, would present a higher risk to develop pulmonary metastasis.

A. Gomez-Brouchet et al.

Galectin-1: marker for osteosarcoma and chondrosarcoma.

Human Pathology (2010) 41, 1220–1230.

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