Objective and importance: Teratomas represent 0.5% of all intracranial tumors. These benign tumors have tissue representative of the three germinal layers: ectoderm, mesoderm, and endoderm. Most teratomas are midline tumors located predominantly in the sellar and pineal regions. Cavernous sinus location is very rare; only two purely intracavernous teratomas have been reported.
Clinical presentation: A 14-year-old boy presented with a history of progressive right eye proptosis and visual acuity impairment, headaches, and a neuralgia-like facial pain in the right V1 distribution. A head computed tomographic scan and magnetic resonance imaging disclosed a large tumor filling the right cavernous sinus and extending into the ipsilateral middle fossa. These scans also demonstrated mixed signals derived from different tissues conforming to the tumor (fat, cartilage, muscle strands, bone, and a primordial tooth). Heterogeneous enhancement was seen after infusion of contrast medium. Significant bone erosion and remodeling was evident in the middle fossa floor and right orbit, with secondary proptosis. A presumptive diagnosis of mature teratoma was made.
Intervention: With the use of a right frontotemporal interfascial approach, a combined extra- and intradural dissection of the tumor was performed. The lesion entirely occupied the cavernous sinus, laterally displacing the Gasserian ganglion and trigeminal branches (predominantly V1 and V2). The internal carotid artery and Cranial Nerve VI were medially displaced by the tumor mass. The lesion was composed of different tissues, including hair, fat, cartilage, muscle, nerve-like tissue, bone, and a primordial tooth. The tumor was removed completely, and the pathological report confirmed the diagnosis of a mature teratoma. There was no evidence of recurrence at the 8-month follow-up examination.
Conclusion: Because of the lesion's location in the lateral wall of the cavernous sinus, a total removal was achieved with the use of standard microsurgical techniques. Knowledge of the microanatomy is essential in treating intracavernous pathology. We present the third reported case of a giant mature teratoma of the cavernous sinus.