Epithelioid Osteoblastoma of the Temporal Bone: A Case Report.

Abstract

Epithelioid osteoblastoma of the cranium is extremely rare and can mimic other etiologies on radiographic imaging, pathology, and symptomatology. An 18-year-old male patient had a 3-week history of a palpable left temporal mass. Magnetic resonance imaging revealed a large, extra-axial, hypervascular mass in the left temporal bone, with bony erosion and intracranial extension. The patient underwent surgical near gross-total resection of the mass. Initial frozen microscopic examination of the tumor was inconclusive. The postoperative course was uneventful, and the patient was discharged a few days later. Final pathology confirmed the diagnosis of epithelioid osteoblastoma. Epithelioid osteoblastoma of the skull base is exceedingly rare but should be included in the differential diagnoses of all extra axial tumors. Preoperative radiographic clues are limited, and final diagnosis relies solely on accurate pathologic examination. A diagnosis of epithelioid osteoblastoma should be considered for all cranial bone-based tumors, as an incorrect diagnosis of another radiographic and histologic mimic could lead to the patient receiving unnecessary and harmful neoadjuvant/adjuvant chemotherapy or radiotherapy.