Differential diagnostic value of "blue reticulated chondroid-like material" in aneurysmal bone cysts: a classic histopathologic analysis of 215 cases.

OBJECTIVES: Our classic histopathologic study of aneurysmal bone cyst (ABC) revealed that "blue reticulated chondroid-like material" (BRC) is characteristic of ABC.
METHODS: The light microscopic findings were retrospectively analyzed in 215 cases of ABC, including 101 primary and 114 secondary cases. In addition, 22 cases of telangiectatic osteosarcoma (TOS) were drawn from the same source and used as a control.
RESULTS: We found the presence of typical BRC in 24 (23.8%) of 101 cases of primary ABC and in six (5.3%) of 114 cases of secondary ABC, with an overall incidence of 30 (14%). None of the cases of TOS showed BRC. BRC was significantly more common in primary ABC than in secondary ABC (P < .05) and in patients 19 years or younger than in those 20 years or older (P < .05).
CONCLUSIONS: BRC appears to be a unique histopathologic feature of ABC, making it valuable to differentiate benign ABC from TOS. Simple H&E stain can be economically performed anywhere. Copyright© by the American Society for Clinical Pathology.