Staffordshire terrier Gizmo, 10 years

Bilateral toe dragging hind limbs, progressive paraparesis

T2 weighted

T2 weighted

T1 weighted without contrast

T1 weighted with i.v. contrast

With kind permission Dr. O. Lautersack, Tierärztliche Klinik für Chirurgie Ettlingen

Diagnosis

MRI description

In the T2 weighted images all included discs show a varying degree of signal loss of the nucleus pulposus. A moderate to severe degree of spondylosis is located at the TL junction and the first three lumbar vertebrae. An approx. 2cm long mass is present to the L of the spinal cord at the level of L2. At the level of the intervertebral foramen L1/2 it causes compression and displacement of the spinal cord to the right. Centrally over L2 the spinal cord is completely abnormal. The transverse images do not indicate if the spinal cord is completely infiltrated or merely severely displaced and compressed. On the T2 weighted dorsal image a “Golf-T sign”, which represents widening of the subarachnoid space, is present cranial and caudal to the lesion. In the T2 weighted images the mass is of heterogeneous hyperintensity, in the T1 weighted images it is hypointense with strong enhancement. A thin structure without contrast enhancement is evident ventral and to the R of L2; its signal intensity is that of the normal spinal cord.

On the sagittal views only part of the LS junction is included. The LS disc appears to protrude moderately into the spinal canal, replacing the ventral epidural fat so that it comes into contact with the cauda equine.

MRI diagnoses

  • Intradural, mostly extramedullary and partially intramedullary mass level with L2
  • Generalised disc degeneration
  • Spondylosis TL junction and cranial L-spine
  • Cauda equine compression secondary to disc protrusion

Discussion

The list of differential diagnoses includes peripheral nerve sheath tumor, lymphoma, malignant histiocytic sarcoma and meningioma. However, the appearance is not typical for the last three tumor types. Localisation and behavior of the mass also fit the diagnosis of neuroblastoma; however, clinical signs generally begin to show between the first and third year of life. In case the tumor is slow growing, the onset of clinical signs can be delayed until later in life.

Outcome

Photo after durotomy.
With kind permission Dr. O. Lautersack.

Gizmo’s owner elected surgery.

During surgery the tumor was intradurally located and had a greasy, friable consistency. Only a partial resection was possible.

The histological diagnosis was atypical meningioma (Grade II WHO).

Two weeks post operatively “Gizmo” had improved significantly and could walk without signs of paraparesis.