CT/MRI Society Case of the Month
August 2006
Sponsored by Eklin Medical Systems
Patient Identification Number: CTMRSOC1
Patient Surname Code: CTMRSOC
Patient First Name Code: BECK
Accession Number: AUGUST06
Contributor: Kathy A Beck
Contributor’s Affiliation: Angell Animal Medical Center- Boston
Species: Feline
Breed: Domestic Shorthair
Age at exam: 9 months
Gender: M/N
Presenting signs and pertinent history:
FeLV+ tests 9/28/05 and 2/28/06. Currently on interferon treatment.
5/14: Originally presented for signs consistent with FLUTD; straining in litter box, “complains when picked up”. Unable to get urine sample, bladder too small. Discharged on antibiotics and pain medication.
5/17: Returned for cystocentesis, no report in record regarding response to therapy or lack thereof.
5/24: Admit to hospital, still straining to urinate and now ataxic.
Clinical/Neuro exam findings:
5/24: Flaccid tail, dribbling urine/incontinent, hind limb ataxia, hyporeflexia of both hind limbs. Pain T-L region.
Relevant Laboratory data:
5/17/06: Normal UA and negative urine culture
5/24/06: CBC: Normal WBC, RBC
Segs: L 1.3 x10^3 (Normal range 2.0-15.5)
Lymphs: H 5.9 x10^3 (Normal range 0.6-5.6)
The clinical pathologist reviewed the cells and considered them to be circulating lymphoma cells
Platelets L 49 x 10^3 (Normal range 200-900) Some clumping observed, but true thrombocytopenia suspected. The cat had no visible clinical signs of a coagulopathy.
Primary clinical rule-out pre imaging: L4-S1 cord level lesion. Based on the clinical signs and the laboratory data spinal lymphoma was the primary rule-out, although FIP is reportedly more common in cats of this age1,2,3. This was explained to the owners, but they still wished to proceed with imaging. The cat developed central neurologic signs post imaging and did not respond to medical management. The clients requested euthanasia at this point.
Modality: MR
Manufacturer: Advanced Veterinary Technologies, Inc
Model/Field Strength: PC1-80/ 1.0T
Sequences Acquired:
Sagittal T1 weighted, Sagittal T2 weighted, Axial T1 and T2, Post-Contrast T1 axial, sagittal and dorsal. (Note: The cat was moved slightly between the pre and post contrast images.)
CT/MR Findings:
Abnormal tissue replaces/infiltrates the normal epidural fat and surrounds the distal cord and filum terminale from the caudal third of L5 vertebral segment to mid L7. This tissue displaces the cord dorsally and circumferentially compresses it. The abnormal tissue is reduced in signal intensity compared to the normal epidural fat on T1-weighted images and is relatively high signal intensity on T2-weighted images. What is believed to be the dural margin can be seen as a dark ring encased by the abnormal tissue on the axial images. There is minimal enhancement post contrast administration. No bone abnormality detected. There is slight loss of hydration of the L6-7 disc.
CT/MR Assessment:
Circumferential extradural “mass” L5-7. Based on MRI appearance and other lab data, epidural spinal lymphoma was suspected
Post Imaging Management:
The owner wanted a confirmed cytological diagnosis and the neurologist suggested that fine needle aspirate could be done. This was done at the L6-7 space via fluoroscopic guidance.
Outcome:
The cat demonstrated central neurologic signs immediately upon recovery from anesthesia post imaging and did not respond to medical management. The client requested euthanasia at this point. No necropsy was performed.
Final Diagnosis based on all diagnostic tests and outcome:
Spinal Lymphoma (large cell type) was diagnosed from the FNA of the epidural lesion.
Comments:
Of note is that this cat did not receive a neurology consultation prior to imaging. Had there been one it is possible that the cat would not have been imaged because our neurologists have been skeptical of our ability to detect epidural lymphoma in cats via MRI. Based on the literature a presumptive diagnosis could have been made based on lab data and neurologic signs. This owner wished to have a confirmed diagnosis and would have pursued treatment had the cat not deteriorated so rapidly after imaging. Since no necropsy was performed it is not known if the imaging procedure or the FNA may have played any role in the cat’s rapid deterioration. Circumferential narrowing of the cord and the visible dark ring of dura is described in the human literature as a classic finding with epidural lymphoma4.
References:
1. Marioni-Henry K, Vite CH, Newton Al, VanWinkle TJ. Prevalence of diseases of the spinal cord of cats. J Vet Intern Med 2004 Nov-Dec;18(6):815-8.
2. Spodnick GJ, Berg J, Moore FM, Cotter SM. Spinal lymphoma in cats: 21 cases (1976-1989). J Am Vet Med Assoc 1992 Feb 1;200(3):373-6.
3. Lane SB, Kornegay JN, Duncan JR, Oliver JE Jr. Feline spinal lymphomsarcoma: a retrospective evaluation of 23 cats. J Vet Intern Med 1994 Mar-Apr;8(2):99-104.
4. Bhatia RG, Sklar EM, Ruiz A, Falcone S. Vertebral and paravertebral abnormalities. In: Edelman RR, Hesselink JR, Zlatkin MB, Crues JV (eds):Clinical Magnetic Resonance Imaging, 3rd ed. Saunders Elsevier, 2006;2335-2336