Neuro_CT_Head: 33 pregnant F, right facial droop, neurological decompensation.

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.

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 
4.6 x 2.9 cm component extending intracranially into the left cerebellopontine and cerebellomedullary cisterns causing marked mass effect and displacement on the brainstem and cerebellum. There is a large associated hematoma associated with this 
mass involving the left cerebellum. The intracranial extension of this mass and associated hematoma causes mass effect in the posterior fossa with downward cerebellar 
tonsillar herniation, and additionally upward transtentorial herniation. The lesion has areas of chondroid appearing matrix
The mass involves the left occipital and temporal bone of the skull base. This mass erodes into the posterior aspect of the proximal left carotid canal extending into the carotid space. There is involvement of the left jugular foramen, with expansion of the left hypoglossal canal to common hypoglossal-jugular foramen cavity. There is involvement of the left middle ear cavity as well as the mastoid portion of the left temporal bone. There is a large extracranial, exophytic component of this mass extending laterally off the left mastoid temporal bone measuring up 
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.
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.

(Petroclival chondrosarcoma)

Accession: CL27388641

Study description: CT HEAD REFERENCE ONLY