Case report: Surgical treatment and long-term successful outcome of a spinal intramedullary vascular malformation in a dog

A 3.5-year-old male intact Staffordshire terrier crossbreed dog was presented with a one-week history of progressive paraparesis with fecal and urinary incontinence. Neurological examination was consistent with a T3-L3 myelopathy. A magnetic resonance imaging study revealed the presence of a well-circumscribed hemorrhagic space-occupying lesion at the level of T12, suspected to be a vascular malformation, such as cavernoma or arteriovenous fistula, primary hematoma or hamartoma; less likely considerations included hemorrhagic inflammation or hemorrhagic primary or secondary neoplasia. A dorsal laminectomy, durotomy, and midline dorsal myelotomy were performed with a surgical microscope, and the vascular lesion was identified and removed. Histological examination of surgical samples yielded fibrin, hemorrhage, hematoidin pigment, and some neural tissue. Although a lining wall was visualized during surgery consistent with a vascular malformation, there was no histological confirmation of such a structure, hampering definitive classification of the lesion. There was no gross or histopathological evidence that would support a diagnosis of a hamartoma or benign neoplasia. The dog was paraplegic with intact nociception the day following surgery. Ambulation was recovered within 2 weeks. Progressive and complete recovery of neurological function was seen over the next 12 weeks. No recurrence of neurological dysfunction was seen over a 12-month follow-up period. Surgical treatment should be considered in dogs with spinal intramedullary vascular lesions which can have a successful long-term outcome.

Case report: Intracranial and spinal subarachnoid hemorrhage in a dog with Angiostrongylosis

A 1-year-old male intact Staffordshire terrier, born and raised in the Netherlands, was presented with a 3-week history of progressive lethargy and spinal, predominantly cervical, hyperesthesia. Other than hyperthermia and cervical hyperesthesia, general and neurological examination did not reveal any abnormalities. Comprehensive hematological and biochemical tests were considered normal. Magnetic resonance imaging of the craniocervical region revealed heterogeneity of the subarachnoid space, characterized by pre-contrast T1W hyperintensity, corresponding to a T2* signal void. Extending from the caudal cranial fossa to the level of the third thoracic vertebra, there were uneven patchy extra-parenchymal lesions that caused mild spinal cord compression, most marked at the level of C2. At this level, the spinal cord showed an ill-defined hyperintense T2W intramedullary lesion. Mild intracranial and spinal meningeal contrast enhancement was evident on post-contrast T1W images. Subarachnoid hemorrhage was suspected, and further diagnostic tests including Baermann coprology resulted in a diagnosis of hemorrhagic diathesis caused by an Angiostrongylus vasorum infection. The dog rapidly responded to treatment with corticosteroids, analgesic medication, and antiparasitic treatment. Follow-up over 6 months yielded complete clinical remission and repeatedly negative Baermann tests. This case report details clinical and magnetic resonance imaging findings in a dog with subarachnoid hemorrhage associated with an Angiostrongylus vasorum infection.

Myelopathy secondary to an intramedullary arteriovenous malformation in a mature dog

A 2‐year‐old crossbreed dog was presented for evaluation of a 6‐week history of progressive paraparesis. Magnetic resonance imaging and computed tomography angiography of the thoracic and lumbar spinal cord disclosed multifocal, anomalous, small, vascular structures, distributed throughout the subarachnoid space of the included section of the spinal cord. An additional focal intramedullary lesion was identified extending from T9 to T10 to T12. Histopathological examination confirmed the presence of an intramedullary arteriovenous malformation affecting the thoracic spinal cord and leading to diffuse congestion and focal hemorrhages into the affected spinal cord.

Surgical Treatment of Suspected Meningioangiomatosis in the Thoracolumbar Spinal Cord

A 5 yr old male neutered Labrador retriever was evaluated for an 8 wk history of a slowly progressive abnormal hind limb gait that did not respond to treatment with nonsteroidal anti-inflammatories. Initial examination findings were mild pelvic limb ataxia and moderate right pelvic limb lameness. A computed tomography with a myelogram was performed and showed a suspected intramedullary spinal mass. MRI was conducted and supported the computed tomography with myelogram findings of a possible intradural spinal mass at L1. A left-sided hemilaminectomy followed by a durotomy at L1 was performed and a firm, tan mass was removed. The histopathologic findings indicated a vascular proliferation most suggestive of a rare proliferative disorder of leptomeningeal blood vessels termed meningioangiomatosis. Although the dog's signs initially worsened after surgery and he was nonambulatory with marked paraparesis, he regained ambulation within 3-4 wk after the operation. Eighteen months after surgery, he was ambulatory with mild hind limb ataxia with no progression of signs. This case suggests that surgical resection of lesions of suspected meningioangiomatosis can result in improvement of clinical signs with a good long-term prognosis.

Remission after complete excision of an intramedullary hemangioma with an identifiable tumor plane in a dog

OBJECTIVE

To describe the use of an identifiable tumor plane (ITP) during myelotomy to excise an intramedullary hemangioma in a dog and report the outcome.

STUDY DESIGN

Case report.

ANIMALS

One 5.5-year-old 42.9-kg spayed female Leonberger dog.

METHODS

Clinical signs included progressive proprioceptive deficits of both pelvic limbs. Magnetic resonance imaging was consistent with a dorsal intramedullary mass at L3-L4. A laminectomy of the third and fourth lumbar vertebrae provided access for dorsal myelotomy. A clear surgical ITP was identified between the intramedullary mass and the spinal cord facilitating complete surgical resection.

RESULTS

Histopathological examination was consistent with a hemangioma. Postoperative MRI was consistent with complete excision of the mass. No evidence of recurrence was found by MRI at 3 months and at 22 months after surgery. Mild proprioceptive deficits persisted in the right pelvic limb.

CONCLUSION

A clear ITP was present, and gross-total resection (GTR) was achieved without significant morbidity. Persistent clinical remission resulted from surgery as the sole therapy.

CLINICAL SIGNIFICANCE

For an intramedullary tumor, GTR is the absence of visible tumor on intraoperative inspection combined with the absence of intramedullary contrast enhancement on postoperative MRI. When an ITP is present, GTR and resultant long-term remission may be more likely.

IMAGING DIAGNOSIS-IMAGING AND HISTOPATHOLOGIC CHARACTERISTICS OF A VERTEBRAL HAMARTOMA IN A CAT

A 9-month-old domestic shorthair cat had progressive ambulatory paraparesis, proprioceptive ataxia, and thoracolumbar hyperesthesia. An extradural mass affecting the left pedicle and lamina of the second lumbar vertebra (L2) causing marked spinal cord impingement was identified in magnetic resonance (MR) images. The mass was predominantly calcified in computed tomographic (CT) images. A hemilaminectomy was performed to resect the mass. Clinical signs were greatly improved at 12-month follow-up. The histopathologic diagnosis was vascular hamartoma. To our knowledge, this is the first report describing the MR characteristics of a vascular hamartoma associated with the vertebral column.

Use of magnetic resonance imaging and histopathologic findings for diagnosis of an aneurysmal bone cyst in the scapula of a cat

CASE DESCRIPTION

An 18-month-old spayed female domestic shorthair cat was evaluated because of left thoracic limb lameness.

CLINICAL FINDINGS

A firm mass was palpable in the left scapular region. On the basis of clinical signs; results of radiographic, ultrasonographic, and cytologic evaluations; and findings on magnetic resonance imaging, an aneurysmal bone cyst (ABC) of the scapula was strongly suspected.

TREATMENT AND OUTCOME

Considering the large size of the mass and the poor prognosis for return to function of the left thoracic limb, amputation was elected. Histologic evaluation ruled out a malignant process and was diagnostic for ABC originating from the left scapula. The patient recovered well and was ambulatory the day after surgery. Three years after surgery, the cat was healthy.

CLINICAL RELEVANCE

The combination of radiography, regional ultrasonography, and magnetic resonance imaging enabled lesion structure and cavity content evaluation. However, final diagnosis was confirmed by histologic evaluation. To our knowledge, this is the first veterinary report of the use of magnetic resonance imaging in the characterization and diagnosis of an ABC.

Compressive Myelopathy Associated With Ectasia of the Vertebral and Spinal Arteries in a Dog

A 4-year-old dog was presented for acute, progressive tetraparesis and cervical hyperesthesia. Symmetrical tubular structures coursing along the lateroventral aspects of the spinal cord at the fourth and fifth cervical vertebrae were identified in magnetic resonance images. At necropsy, vertebral arteries and their spinal branches were severely ectatic bilaterally, and the cervical spinal cord was compressed. Histologically, the ectatic branches of the vertebral and ventral spinal arteries were surrounded by fibrosis with scant mononuclear cell infiltrates and hemorrhage. Spinal branches of the vertebral arteries had focally severe reduction in the tunica media. A thrombus was in an arterial branch. Smaller vessels in adjacent tissue had fibrinoid degeneration. Axonal degeneration was detected in the affected spinal cord and nerve roots. The segmental degenerative radiculomyelopathy in this dog was attributed to anomalous ectasia of the vertebral and ventral spinal arteries.