Associated aneurysmal bone cyst and cemento-osseous dysplasia: a case report and review of the literature.

The purpose of this case report is to describe a previously unpublished association between focal cemento-osseous dysplasia (FCOD) and an aneurysmal bone cyst (ABC) and review the literature with regard to associated benign fibro-osseous lesions and cysts. A 41-year-old woman without a history of trauma presented with asymptomatic swelling in the right side of the mandible. Radiographs of the region revealed a unilocular radiolucent area with radiopaque foci. After aspiration of the lesion was positive for serosanguineous fluid, complete excision of the lesion was performed. Microscopic examination revealed a hybrid ABC and FCOD. The 12-month follow-up showed significant bone repair and no signs of recurrence. A review of the English-language literature from 1980 to 2012 revealed 1 retrospective study, 4 case series, and 18 single-case reports on the topic of cemento-osseous dysplasias, fibro-osseous lesions, and aneurysmal bone cysts. Of 59 cases, none reported an association between an ABC and FCOD. Although fibro-osseous lesions do not require intervention, surgical excision is recommended when they are associated with cysts. This case, in which an ABC and FCOD were associated, reinforces the need for a careful diagnostic process in radiographically mixed lesions that respond positively to aspiration biopsy.