CLINICAL HISTORY: 33-year-old female, 25 weeks pregnant, presented with sudden onset worst headache of her life, vertigo nausea and vomiting. In ED noted to have mild right facial droop, slurred speech and facial deformity. Past medical history is notable for 2 prior
resections of mass behind the left ear, last in 2010.
FINDINGS:
Large multilobulated mass is seen involving the left skull base, measuring up to 10 x 6 cm in transaxial dimension and extending over 6.6 cm craniocaudally. This mass has a
mass involving the left cerebellum. The intracranial extension of this mass and associated hematoma causes mass effect in the posterior fossa with downward cerebellar
to 3.4 x 6.1 cm in size.
Orbits: Normal.
Visualized paranasal sinuses: Clear.
Mastoid air cells: Right mastoid air cells are clear.
Brain parenchyma: No acute infarction or parenchymal mass. Large left skull base mass causing mass effect on the cerebellum and brainstem as above.
Ventricles and extra-axial spaces: There is moderate lateral and third ventricular
enlargement with periventricular edema consistent with hydrocephalus. There is new blood layering within the bilateral occipital horns of the lateral ventricles as well as the third ventricle.
IMPRESSION:
1. Large 10 x 6 x 7 cm left skull base mass
predominantly involving the left temporal and occipital bones with areas of chondroid appearing matrix, most suggestive of a chondrosarcoma. This mass has a 4.6 x 2.9 cm component extending intracranially into the left cerebellopontine and cerebellomedullary cisterns with associated 2.7 x 4 cm hematoma along the posterior aspect of the mass in the left cerebellum. Combination of this mass and hematoma cause mass effect on the brainstem and cerebellum and with resultant downward
cerebellar tonsillar herniation and upward transtentorial herniation. Hemorrhage is of uncertain etiology, may be extension of tumoral hemorrhage or due to venous hypertension given involvement
of the left sigmoid sinus and jugular foramen.