CT/MRI Society Case of the Month
October 2006
Sponsored by Eklin Medical Systems
Patient Identification Number: CTMRSOC1
Patient Surname Code: CTMRSOC
Patient First Name Code: KRAMER
Accession Number: OCT06
Contributor: Robert Kramer
Contributor’s Affiliation: Veterinary Radiology, Mountlake Terrace, WA
Species: K9
Breed: Cane Corso
Age at exam: 9 yr
Gender: FS
Presenting signs and pertinent history:
Seizure activity, behavioral changes.
Clinical/Neuro Exam Findings:
Anisocoria with dilated right pupil, right temporalis muscle atrophy, depressed mentation.
Relevant Laboratory data: None
Primary clinical rule-out pre imaging:
Mid-brain floor tumor affecting CN III and V
Modality: CT
Manufacturer: GE Medical
Model/Field Strength: CT/i
Sequences Acquired Pre- and Post-Contrast:
Pre-contrast and post-contrast transverse plane 3mm slices obtained with helical technique, overlapping.
CT/MR Findings:
There is moderate atrophy of right temporalis musculature. The right mandibular salivary gland is enlarged and enhances markedly and heterogeneously. The left salivary gland is enlarged similarly but exhibits uniform contrast enhancement. A thin extension of enhancing tissue apparently originating within the right mandibular salivary gland migrates dorsally and rostrally and invades the canal for the trigeminal nerve. This canal is abnormally expanded and there is a defect in the bone covering the dorsal aspect. The enhancing tissue continues through the trigeminal canal and invades the calvarial space ventral to the brain, with extension rostrally into the cavernous sinus and right orbital fissure, and caudally into the space immediately to the right of the brainstem/spinal cord transition; the cord is displaced minimally to the left. The right side of the cavernous sinus is enlarged and the dorsum sellae is asymmetric with minimal dorsal displacement of the right caudal clinoid process. The diameter of the right orbital fissure is slightly greater than the left. There is also enlargement of the right alar foramen, with likely extension of tissue within this lesion.
No evidence of brain invasion or abnormal leptomeningeal enhancement is identified.
CT Assessment:
1. Enlarged and abnormally enhancing right mandibular salivary gland.
2. Uniformly enhancing left mandibular salivary gland.
3. Moderate right temporalis muscle atrophy.
4. Enhancing tissue with potential origin from trigeminal nerve or the right salivary gland, which extends into the right calvarial floor and invades or compresses the cavernous sinus, orbital fissure, alar foramen, and trigeminal canal.
5. Mild leftward displacement of the C1 segment of the spinal cord.
6. Enlargement of the spaces within the orbital fissure, trigeminal canal, and alar foramen, suggestive of diffuse disease within trigeminal nerve and associated branches.
Post Imaging Management:
Client declined salivary gland biopsy or neurologist referral. Corticosteroid therapy initiated at anti-inflammatory levels.
Outcome:
Euthanasia four weeks after imaging. Skull necropsy performed by ACVP Diplomate.
Final Diagnosis based on all diagnostic tests and outcome:
1. Salivary gland adenocarcinoma, multifocal, with peripheral stromal and vascular invasion, high grade, multiple submandibular salivary glands. (right side)
2. Sialoadenitis, multifocal to coalescing, moderate, chronic with ductular ectasis and inspissated mucinous material, multiple salivary glands. (left side)
3. Lymphoid follicular hyperplasia, diffuse, moderate to severe with sinus hemorrhage, congestion and hemosiderosis, submandibular and cervical lymph nodes.
4. Multifocal, mild perivascular glial call proliferation, brain.
Comments:
From the pathology report:
"Samples of tissue from the mass within the ventral midline contain an effaced salivary gland, with an expansile salivary gland adenocarcinoma......."
"Samples from a multilobular mass coursing along the path of the right trigeminal nerve contains a multilobular adenocarcinoma, effacing salivary gland architecture, with abundant stromal invasion, vascular invasion, occasional invasion of vessels adjacent to the trigeminal nerve, although cross sections of the nerve are normal."
"The neoplasm surrounds the trigeminal nerve, and extends around the right tympanic bullae, is likely associated with neurogenic atrophy of the temporalis muscle. There is abundant vascular invasion of neoplastic cells, although regional lymph node invasion is not definitively seen.
3D rendering using Osirix software and Mac Pro workstation.