Solid variant of aneurysmal bone cyst with a novel (X;9) translocation

Aneurysmal bone cysts (ABC) are locally destructive bone lesions occurring predominantly in young adults. There has been debate as to the neoplastic nature of these lesions. In recent years, however, compelling evidence of clonal chromosomal abnormalities has indicated a likely neoplastic origin. Although relatively few ABC have been assessed cytogenetically, many of those which have been studied have shown abnormalities of chromosome 17, particularly t(16;17)(q22;p13). We present a case of ABC in a 4-year-old female, which demonstrated the novel translocation t(X;9)(q26;q32).