Skull Base Complications after Medical Treatment of Skull Base Tumors: Case Illustrations

Tumors involving the skull base often undergo nonsurgical treatment such as chemotherapy or radiation as primary therapy. Risks typically associated with surgical resection include injury to adjacent vital structures (carotid artery, brain parenchyma, optic nerves), infection and cerebrospinal fluid (CSF) leak. We discuss the management of two patients who presented with spontaneous skull base defects secondary to nonoperative treatment of their tumors.

The first patient was a 74-year-old female with sinonasal undifferentiated carcinoma (SNUC) invading the anterior skull base and left medial orbit that developed a CSF leak and pneumocephalus after her second round of neoadjuvant chemotherapy with platinum etoposide. There was a dramatic response of her tumor to chemotherapy allowing safe surgical resection and repair of the skull base defect.

The second patient was a 46-year-old with a macroprolactinoma that developed a CSF leak after being treated with cabergoline (DA). The patient underwent endonasal surgical repair using a pedicled nasoseptal flap.

Though CSF leak and pneumocephalus are typically considered to be complications of surgical management of skull base tumors, these two cases demonstrate that they are risks of medical management as well. As skull base tumors grow, they may cause the destruction of the osseous boundaries separating the intracranial cavity from the paranasal sinuses. They occupy this space similar to a plug, in doing so preventing communication between these two spaces. Our patients had such tumors and went on to develop complications after medical therapy wherein tumor shrinkage exposed the skull base defects created by these tumors leading to pneumocephalus and CSF leak. Both were successfully treated with endonasal surgical repair. Clinicians should be aware of this rare, but potentially dangerous complication when monitoring patients undergoing medical therapy for skull base tumors.