Extract
Aneurysmal bone cyst is an expansile, destructive, hemorrhagic,
non-neoplastic lesion that is thought to represent a benign reactive vascular
process1-4.
These lesions have been designated as either primary or
secondary, with the latter term used when histological evaluation
indicates a coexisting lesion, which can be either benign or
malignant5,6.Occasionally, telangiectatic osteosarcomas have been misdiagnosed as
aneurysmal bone
cysts7-9,
but the true nature of the malignant tumors usually became apparent after
rapid progression or
recurrence7. Like
other benign tumors, aneurysmal bone cysts have been reported to have
undergone malignant transformation, although most of the transformations were
induced by
irradiation7,10,11.
In a review of the literature, only two well-documented reports of malignant
transformation of an aneurysmal bone cyst without a history of irradiation
were found. One transformation was to a malignant fibrous histiocytoma, and
the other was to an
osteosarcoma7,12.