Multi-compartment skull base orbital cavernous venous malformation: A rare presentation of a common orbital mass

PURPOSE: We present a unique case of an orbital intraconal cavernous venous malformation that extended along the trigeminal nerve to the pterygopalatine and middle cranial fossa. Our aim is to describe an atypical presentation of this common orbital vascular mass. OBSERVATIONS: A 57-year-old female presented with right eye proptosis. Orbital magnetic resonance imaging demonstrated a lobulated contrast-enhancing mass involving the right intraconal orbital space, pterygopalatine fossa, and right middle cranial fossa, radiographically presumed to be a schwannoma. Intraoperative and histopathologic evaluation confirmed a cavernous venous malformation that extended along the trigeminal nerve. The mass, including its attachments to the cranial nerves and dura, was successfully removed via a combined transorbital and endoscopic endonasal approach. The patient recovered well with 20/20 vision, full extraocular movements, and resolution of proptosis. CONCLUSIONS: This a rare presentation of an orbital cavernous venous malformation not previously described. Cavernous venous malformations typically present as ovoid well-circumscribed lesions; however, they can also extend outside the orbit along the path of cranial nerves, as was observed in this case. These types of lesions should be included in the differential diagnosis of masses arising from or extending along cranial nerves, even when involving the orbit.