Two secondary aneurysmal bone cysts associated with mandibular fibrous dysplasia: a rare case and literature review.

Introduction and importance: The aneurysmal bone cyst (ABC) is an expansive, destructive, non-odontogenic, and benign bone lesion characterized by spaces filled with blood, typically affecting the elongated bones and spine, with a low incidence in the maxillofacial region. The pathogenesis may occur due to prior or pathological trauma, arteriovenous malformation, secondary association with a pre-existing bone process, such as giant cell tumor, ossifying fibroma, and bone dysplasia, or even genetic alterations. Managing an ABC involves different methods. The preferred treatment is surgical resection for the complete removal of the lesion, thereby reducing the recurrence rate. Case presentation: This study reports a rare case of two secondary ABCs of the mandible arising from pre-existing fibrous dysplasia, detailing the surgical management and recurrence over a 9-year follow-up period. Clinical discussion: This report highlights the clinical, radiological, and histopathological characteristics of mandibular ABCs and emphasizes the importance of accurate diagnosis and comprehensive surgical management to prevent recurrence. Conclusion: The case underscores the diagnostic challenges in differentiating primary ABCs from secondary lesions arising within other fibro-osseous conditions, as well as the need for long-term follow-up to monitor potential relapse.