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Introduction: Epidermoid tumors comprise 1% of intracranial tumors. Although reported,
intraosseous epidermoid tumors are even more rare. Cystic lesions of the petrous apex
are uncommon and surgically challenging; the most rare pathology is presumed to be
epidermoid.
Case Presentation: This is a case of a 61-year-old woman with a large skull-base tumor extending
inferiorly from the C1-C2 articulation and superiorly to the tuberculum sella.
The lesion replaced the left-sided petrous apex, and the lateral extension of the tumor
reached the styloid process. The tumor displayed intradural invasion medial to the internal
auditory meatus, producing an intra-axial mass at the level of the upper pons.
The patient presented with a 4-month history of headache and total unilateral deafness.
Under image guidance, an endoscopic endonasal approach was used to totally resect the
tumor. By following the tumor’s dural defect, the intra-axial part of the tumor was safely
resected, and the dural defect was successfully repaired.
Conclusions: Image-guided endoscopic endonasal surgery is a versatile approach that
can safely and easily address a large epidermoid tumor in this challenging region, obviating
the need for demanding and sophisticated transcranial surgery.