Meningioangiomatosis associated with fibrous meningioma in a dog

Vertebral Angiomatosis in a Dog

A 3 yr old spayed female Cavalier King Charles spaniel was referred for insidious ataxia and paraparesis. A thoracolumbar lesion was suspected. Computed tomography showed focal osteolysis of the vertebral body and pedicles of T5. In addition, a hyperdense, extradural material within the vertebral canal, causing spinal cord compression on the right side, was present. The lesion was confirmed with magnetic resonance imaging. A T4-T5 hemi-dorsal laminectomy was performed to decompress the spinal cord. Histopathological examination was consistent with vertebral angiomatosis. After the surgery, the dog rapidly improved; however, 5 mo later the clinical signs relapsed. Vertebral angiomatosis is a vasoproliferative disorder, rarely reported as a cause of myelopathy in cats. This condition has not previously been reported in dogs. This case report describes the clinical features, the diagnostic findings, and the follow-up of a young dog with vertebral angiomatosis.

Domestic Animal Models of Central Nervous System Tumors: Focus on Meningiomas

Intracranial primary tumors (IPTs) are aggressive forms of malignancies that cause high mortality in both humans and domestic animals. Meningiomas are frequent adult IPTs in humans, dogs, and cats, and both benign and malignant forms cause a decrease in life quality and survival. Surgery is the primary therapeutic approach to treat meningiomas, but, in many cases, it is not resolutive. The chemotherapy and targeted therapy used to treat meningiomas also display low efficacy and many side effects. Therefore, it is essential to find novel pharmacological approaches to increase the spectrum of therapeutic options for meningiomas. This review analyzes the similarities between human and domestic animal (dogs and cats) meningiomas by evaluating the molecular and histological characteristics, diagnosis criteria, and treatment options and highlighting possible research areas to identify novel targets and pharmacological approaches, which are useful for the diagnosis and therapy of this neoplasia to be used in human and veterinary medicine.

Encephalic meningioangiomatosis in a dog with high-grade undefined glioma

Meningioangiomatosis (MA) is a rare proliferative meningovascular disorder that affects mainly the cerebral cortex, brainstem and spinal cord of humans and animals and can coexist with other proliferative disorders. A 7.5-year-old male Brazilian Campeiro Bulldog died after a convulsive crisis and cardiorespiratory arrest. At necropsy, a firm, white mass involving the piriform and right occipital lobes was seen. Histologically, the mass consisted of two morphologically distinct entities that collided: a congenital malformation characterized by a proliferation of meningothelial cells around blood vessels, within the perivascular spaces; and a neoplasm composed of two cell populations with astrocytic and oligodendrocytic differentiation. Meningothelial cells and neoplastic glial cells immunolabelled for vimentin. This first reported case of encephalic MA with a high-grade undefined glioma in a dog was confirmed through clinical signs, pathological and immunohistochemical findings.

Encephalic meningioangiomatosis in a cat

Meningioangiomatosis (MA) is a rare proliferative meningovascular entity that has been described mainly in humans and dogs. Here we describe MA in a 13-y-old spayed female domestic shorthaired cat that died 5 d after acute change in behavior, open-mouth breathing, seizures, hyperthermia, and inability to walk. On MRI, the lesion appeared predominantly as extraparenchymal hemorrhage. Autopsy changes consisted of a dark-red, hemorrhagic plaque that expanded the leptomeninges and outer neuroparenchyma of the right piriform and temporal telencephalic lobes, chalky white nodules in the peripancreatic fat, and yellow fluid in the abdomen. Histologically, the lesion in the brain consisted of leptomeningeal thickening by spindle cells that effaced the subarachnoid spaces and extended perivascularly into the underlying cerebral cortex. Spindle cells were arranged as streams or whorls around blood vessels, and had slender eosinophilic cytoplasm and elongated nuclei with coarsely stippled chromatin and 1 or 2 distinct nucleoli. There was extensive hemorrhage, clusters of hemosiderin-laden macrophages, and mineralization throughout. Spindle cells had positive immunolabeling for vimentin. A striking MRI and gross feature in our case was the extensive hemorrhage associated with the MA lesion. Additional findings included suppurative pancreatitis with peritonitis and supraspinatus myonecrosis.

A Review of Proliferative Vascular Disorders of the Central Nervous System of Animals

In disease, blood vessel proliferation has many salient roles including in inflammation, when granulation tissue fills superficial defects, or in the recanalization of an occluded blood vessel. Sometimes angiogenesis goes awry-granulation can be exuberant, and plexiform proliferation of vascular components can contribute to pulmonary hypertension. This review focuses on the diverse manifestations of pathologic vascular overgrowth that occur in the brain, spinal cord, and meninges of animals from birth until old age. Entities discussed include systemic reactive angioendotheliomatosis in which glomeruloid vascular proliferations are encountered in various organs including the central nervous system (CNS). The triad of CNS vascular malformations, hamartomas, and benign vascular proliferations are an especially fraught category in which terminology overlap and the microscopic similarity of various disorders makes diagnostic classification incredibly challenging. Pathologists commonly take refuge in "CNS vascular hamartoma" despite the lack of any unique histopathologic features and we recommend that this diagnostic category be abandoned. Malformative lesions that are often confusing and have similar features; the conditions include arteriovenous malformation, cavernous angioma, venous angioma, and capillary telangiectases. Meningioangiomatosis, a benign meningovascular proliferation with dual components, is a unique entity seen most commonly in young dogs. Last, accepted neoplastic conditions range from lower-grade locally acquired growths like hemangioblastoma (a tumor of mysterious interstitial stromal cells encountered in the setting of abundant capillary vasculature proliferation), the rare hemangioendothelioma, and the highly malignant and invariably multifocal metastatic hemangiosarcoma. Additionally, this review draws on the comparative medical literature for further insights into this problematic topic in pathology.

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.