Aggressive (epithelioid) osteoblastoma camouflaged by pain associated with erupting third molars—case report and literature review

Clinical Presentation

A 16-year-old patient was referred for extraction of third molars and supernumerary tooth distal of #17, as he had been experiencing pain in the left mandible. The pain persisted for more than 2 weeks after extraction of #17. Although the extraction site demonstrated good initial healing, there was evidence of significant bony expansion lingually with mobile #18 and 19. This had shown significant progression since the preoperative examination. A panoramic study showed resorption of distal root #19. Cone beam computed tomography scan was performed and showed a large, expansile, ill-defined, mixed density but predominantly radiolucent lesion. In addition, disruption of the lingual cortex and superior border of inferior alveolar canal was observed with no signs of paresthesia clinically.

Differential Diagnosis

Expansile bone tumors of jaw with resorption would include cemento-ossifying fibroma, osteoblastoma and osteosarcoma.

Diagnosis and Management

Histopathologic examination revealed an epithelioid neoplasm consisting of clusters of round epithelioid cells surrounding blue lace-like bony trabeculae (osteoid). Cytomorphology was bland and mitoses were occasionally seen. A diagnosis of aggressive (epithelioid) osteoblastoma was rendered. Management involved en-bloc resection with wide margins as epithelioid osteoblastoma has a high recurrence rate of almost 50%.

Conclusions

Aggressive (epithelioid) osteoblastoma, a rare histological subtype of osteoblastoma, shows a tendency for local invasion and high recurrence rate. Few cases have been reported in the jaws, with the mandible more commonly affected than the maxilla. The presence of pain from the emerging third molar and subtle clinical and radiologic evidence before extraction were the culprits which the lesion was not initially detected. Otherwise, the intense clinical expansion following extraction, location, and radiographic characteristics of this case appear to be consistent with the cases reported in the literature. Closely follow-up is recommended to monitor possible recurrence.