Recurrent simple bone cyst of the mandibular condyle: a case report
A healthy 16-year-old boy was referred for the evaluation and management of an asymptomatic radiolucency of the left mandibular condyle that was noted on a routine panoramic radiograph. A history of no trauma was elicited, and the familial and medical histories were not contributory. Physical examination revealed a slight mandibular laterognathism, normal mandibular excursions, and a painless range of motion in spite of class III malocclusion. The occlusion was unstable, and clicking sounds were detected at the right temporomandibular joint (TMJ) during mouth opening. No cervical lymphadenopathy was detected, and no intraoral swelling or deformity was visible.\nA panoramic radiograph showed a well-defined multilocular radiolucent lesion located in the left mandibular condyle. The mandible was deviated to the left side due to hypertrophy of the right mandible. Multiple lower anterior teeth were tilted to compensate for the hemimandibular hypertrophy, and the occlusal relationship was poor on maximum occlusion (). The cone-beam computed tomography (CBCT) scans showed that the lesion was an amorphous multilocular lytic lesion that had a thinned, well-defined, and scalloped cortical border in some parts (). The enhanced computed tomography (CT) scans revealed a non-enhanced multilocular lesion, which had CT values from -10 to 8 Hounsfield units (HU) (). Magnetic resonance imaging (MRI) showed homogeneous intermediate signal intensity (SI) on T1-weighted images and homogeneous high SI on T2-weighted images, with a clear border in both images. The articular disc of the TMJ was located in a normal position (). A tentative radiographic diagnosis of the simple bone cysts was made, and central giant cell granulomas and aneurysmal bone cysts were included in the differential diagnosis of the lesion.\nSurgery was performed under general anesthesia through an incision of the left posterior vestibule. The half of the mandibular ramus containing the mandibular condyle was rejected and eviscerated. The condylar defect with a partially thin cortical plate was revealed. The cortical plate was removed in parts, and the internal walls of the cavities were lightly curetted (). Small amounts of tissue obtained from the defect for microscopic examination were negative for epithelium. The eviscerated bone segment was repositioned to its original state and fixed with miniplates.\nMicroscopic examination of the specimen showed a cystic lesion without an epithelial lining, which was surrounded by dense fibrous connective tissue. Osteoid bone was also seen in the connective tissue indicating reactive bone formation. These features were consistent with those of simple bone cysts ().\nA 14-month postoperative radiographic follow-up showed a recurred lesion at the left mandibular condyle. The lesion had recurred on the previously scalloped part. It showed radiolucency with an expanded, scalloped cortical plate on the CBCT images. A second surgical excision was performed using the preauricular approach. The microscopic features were similar to those of the initial biopsy specimen.\nThe 6-month postoperative recovery was unsatisfactory even though there was no sign of recurrence. The patient was treated for hemihypesthesia of the left lower face due to a left facial nerve injury followed by a pre-auricular surgical approach.