Left transorbital transpterygoid biopsy of skull base lesion via orbitotomy: A case report

Background The PPF is a difficult-to-access, pyramidal-shaped zone located behind the maxillary sinus that contains multiple critical neurovascular structures. Minimally invasive approaches, such as endoscopic endonasal approaches (EEA) with or without endoscopic transorbital (ETOA) approaches, have largely replaced traditional open facial incisions when possible. However, there is limited literature describing the feasibility of biopsying and debulking lesions in the PPF using the ETOA alone. Case Description We present the case of a 77-year-old male with left facial numbness and a lesion in the region of the foramen rotundum initially presumed to be a trigeminal schwannoma/neuroma. Surveillance imaging revealed progressive nodular, heterogeneous enhancement and robust diffusion restriction along the V2 segment from Meckel’s cave through the foramen rotundum and into the PPF. Given worsening symptoms and concern for tumor growth, the patient underwent an ETOA via an inferior transconjunctival incision for biopsy and debulking. Subperiosteal dissection of the orbital floor and removal of the posterior maxillary sinus wall exposed the PPF, allowing debulking of the lesion through the enlarged infraorbital nerve. Outcome Pathology revealed a malignant epithelioid neoplasm admixed with spindle-cell components, most consistent with a carcinoma arising within, or colliding with, a trigeminal schwannoma. The patient recovered well postoperatively and was discharged on postoperative day one with no new deficits. Conclusion This case demonstrates that the ETOA alone can offer a safe, direct, and minimally invasive route for biopsy and debulking of select V2 lesions extending into the PPF, providing an alternative to traditional open or combined endoscopic approaches.