Large Subtentorial Extraaxial Intracranial Mass: our Case of the Month April, 2024

The SonoPath Imaging Center located in Andover NJ captured the diagnostic images for this intracranial mass with interpretation by specialist Nele Eley, DVM, Dr. med. Vet. DipECVDI (Radiology). This case was referred to us by Animal Hospital of Sussex County, treatment management by Dr. Courtney.


 The CT study reveals an extraaxial intracranial mass within the caudal cranial fossa. The mass is in a subtentorial position and measures 16mm in length, 13mm in height, and 15mm in width. Moderate nonuniform contrast enhancement is seen. Imaging exhibits hyperattenuating areas on the plain scan. Mild hyperostosis of the osseous tentorium of the cerebellum is noted. 

Both tympanic bullae contain a moderate amount of fluid attenuating material, L>R. Thickening of the mucosal lining of the right and left tympanic bullae is seen. The osseous lining is smooth and thin. A moderate amount of hypoattenuating contrast negative material is seen within the medial aspect of the left external auditory meatus. The right external auditory meatus presents within normal limits at this time. 

The regional lymph nodes in the retropharyngeal space present mild symmetric enlargement. 

Multiple metal opaque bullet fragments are seen within the left nasal cavity and circumferential to the left maxilla and temporomandibular joint. No evidence of osseous injury is noted; however, there is moderate atrophy of the left masseter muscle. 


  • Large extraaxial intracranial subtentorial mass with significant mass effect onto the cerebellum and cerebellar herniation. 
  • Chronic bilateral otitis media. 
  • Chronic left-hand sided otitis externa. 
  • Mild bilateral retropharyngeal lymphadenomegaly compatible with reactive lymphadenitis. 
  • Old air gun injury with left masticatory muscle atrophy. 


 The CT study reveals a large subtentorial extraaxial intracranial mass. The findings are compatible with subtentorial meningioma. Round cell neoplasia is a potential but less likely differential diagnosis. Increased intracranial pressure and foraminal herniation of the cerebellum have to be assumed. 

The CT study furthermore confirms presence of bilateral otitis media and left-hand sided otitis externa with reactive regional lymphadenitis and chronic traumatic injury secondary to multiple air gun bullet fragments in the region of the left mandible and left temporomandibular joint as well as within the left nasal cavity. The isolated masseter muscle atrophy indicates potential injury of one of the peripheral branches of the mandibular nerve and/or chronic disuse. 


Low dose Gabapentin was given 2 hours prior to drop off time for the patient’s CT scan.

A male neutered, 11-year-old domestic short hair feline presented for BB pellets noted in radiographs. Patient exhibited vestibular signs, chronic ear infection, and pain in neck, especially when head is turned to the left side.

Abnormal PE/Chem/CBC/UA Results:

Sodium 146 Low end of normal ( 147 – 157 mmol/L) Chloride 113 Low end of normal (114 – 126 mmol/L) 

Bullae found in CT scan.

SonoPath Imaging Center

High-quality diagnostic imaging plays an important role in providing an accurate diagnosis, which is why the SonoPath Imaging Center has heavily invested in the best, state-of-the-art imaging equipment in veterinary medicine. When you refer your client and their pet to the SonoPath Imaging Center, our team will collaborate with you and your clinic to ensure a seamless level of care.

What Services does The Imaging Center Provide?

Computed Tomography Applications