Central Nervous System B-cell Lymphoma in a Bald Eagle ( Haliaeetus leucocephalus)

An adult bald eagle ( Haliaeetus leucocephalus) presented for nystagmus and an inability to fly. On physical examination, the eagle was open-mouth breathing and tachycardic at 200 beats per minute, had a wrinkled cere and sunken eyes, and was an estimated 10% dehydrated. Additionally, the eagle was extremely weak, with neurologic abnormalities including bilateral proprioceptive deficits, nystagmus, and no pupillary light reflex in the left eye. Despite aggressive treatment, the eagle continued to decline rapidly and subsequently died. On histologic examination, diffuse and widespread infiltration of neoplastic lymphocytes was present in the brain, optic nerves, and pecten. Immunohistochemical PAX-5 labeling confirmed B-cell lymphoma confined to the eye and nervous system. Test results for select avian retroviruses, Marek's disease, West Nile virus, avian influenza viruses, and Mycoplasma were negative. To our knowledge, this is the first report of B-cell lymphoma in a bald eagle. Although rare, this condition is a differential diagnosis in cases of neurologic or ocular diseases in birds.

Low-grade Glial Tumor with Features of Astroblastoma in a Dog

A 12-year-old, neutered, male Belgian Malinois/Great Dane cross dog presented with a 5-month history of weakness and lack of endurance followed by acute onset of rear limb ataxia. At autopsy, a 9 x 16 mm, multilobular, firm, white to tan, expansile mass was found in the cerebellum. Mild dilatation of the lateral ventricles was also noted. Histologically, there was a well-demarcated glial neoplasm composed of medium-sized astrocytic elements that had homogeneous cytoplasm, sometimes with globular eosinophilic inclusions, irregular peripherally located nuclei with a single nucleolus, and short cytoplasmic processes. Prominent peri-vascular pseudorosettes with cellular processes in contact with blood vessels were present. Some blood vessels exhibited hyalinized walls. Mitotic figures were not observed. Immunohistochemically, neoplastic cells expressed glial fibrillary acidic protein and vimentin. These features are consistent with an astroblastoma. This is the first clinicopathologic correlation and detailed description of a low-grade glial tumor with features of astroblastoma in a dog.

Magnetic resonance imaging features of cerebellar vermis medulloblastoma in an adult canine patient

A seven-year-old, not-castrated male, Airedale Terrier presented with a history of ataxia and intention tremor of the head of three-week duration. Neurologic examination demonstrated severe hypermetria, intention tremor of the head and a bilateral menace response deficit. Magnetic resonance imaging revealed a well demarcated cerebellar vermis mass, hypointense on T1-weighted images, hyperintense on T2-weighted images, with multiple small foci of high signal similar to that of CSF. Foci dispersed in the mass creating a speckled appearance. Homogeneous faint, wispy post-contrast enhancement of the mass was noted; as a result the tumor became isointense to gray matter and was not clearly evident in post contrast images. The histopathological diagnosis of the excised tumor was cerebellar medulloblastoma.

[Case-report. Malignant nerve sheath tumor in a cow with symptoms of suspected BSE]

We report here on a 3 1/2-year-old mother cow with a malignant perineural tumour near the pontine angle of the cerebellum, but which first drew attention because of clinical signs of BSE. Neurological symptoms that manifested during the course of the disease included disturbances in behaviour, movement and aesthesia, as described by BRAUN et al. (2001) in cases of BSE. Inconsistent with a diagnosis of BSE were focal neurological disturbances (head held aslant to the right, tendency to fall to the right, right-sided facial weakness, left-sided nystagmus and ventral strabismus). Following euthanasia, magnetic resonance imaging (MRI) revealed a tumour in the cerebellopontine angle. Histological findings describe a malignant peripheral nerve tumour of the vagal nerve with rhabdoid differentiation (a so-called Triton tumour) with an intracranial and an extracranial part.

Cerebrospinal fluid from a dog with neurologic collapse

A 3-year-old Staffordshire Terrier was presented to the Texas Veterinary Medical Center with a short progressive history of anorexia, weight loss, and weakness that had progressed to ataxia and collapse with empirical treatment. The dog was tetraparetic and obtunded. Results of a complete neurologic evaluation were consistent with severe, multifocal to diffuse disease involving the forebrain, spinal cord, and brainstem. Cerebrospinal fluid, obtained via cerebellomedullary cisternal puncture, was highly cellular and contained large atypical round cells with small numbers of nondegenerate neutrophils and large mononuclear cells. Rare eosinophils and small lymphocytes were noted. The atypical round cells were approximately 15-25 micro m in diameter with a single nucleus set in a small amount of cytoplasm. The nuclei were typically round to slightly ovoid; however, occasional notched, lobulated, and reniform nuclei were observed. These cells were interpreted as malignant lymphocytes. Owing to a grave prognosis, the animal was euthanized and a necropsy was performed. No gross lesions were found in the central nervous system. Multiple sections of cerebellum, medulla, and spinal cord contained a diffuse neoplastic infiltrate that was predominantly meningeal with rare superficial neuropil invasion. The neoplastic cells were arranged in sheets, cords, and rosettes. Immunohistochemical staining for vimentin, pancytokeratin, CD3, CD79a, synaptophysin, S-100, and neuron-specific enolase was negative; glial fibrillary acidic protein (GFAP) staining was equivocal. Based on histologic findings, a diagnosis of medulloblastoma was made. This case documents the rare occurrence of a canine medulloblastoma and illustrates the difficulty in distinguishing between some embryonal brain tumors and lymphoma.

Magnetic resonance imaging findings of an intracranial medulloblastoma in a Polish Lowland Sheepdog

Medullobastoma is an uncommon caudal fossa tumor. The imaging features of medullobastoma in the dog are poorly described. In this report, the magnetic resonance (MR) appearance of a cerebellar medullobastoma in a dog is described. The MR features were similar to medulloblastomas in adult humans, with the tumor arising laterally and extending to the surface of the cerebellar hemisphere. Correct localization of medulloblastoma may be difficult and it should be considered as a differential for both extra- and intra-axial caudal fossa masses.

Astrocytomas in young dogs

Primary brain tumors are not commonly reported in young dogs; however, they are the second most common cancer in children. Astrocytomas are the majority of these tumors. This report presents three cases of astrocytomas in young dogs, indicating a possible higher incidence than what is currently held. When suspected, it is recommended that biopsy or surgical excision be performed to further characterize and grade the tumor and, if appropriate, guide treatment.

In vivo antitumor activity of S16020, a topoisomerase II inhibitor, and doxorubicin against human brain tumor xenografts

New active drugs are needed for the treatment of primary brain tumors in both children and adults. S16020 is a cytotoxic olivacine derivative that inhibits topoisomerase II. The aim of the study was to determine its antitumor activity in athymic mice bearing subcutaneous medulloblastoma (IGRM33, 34, 57) and glioblastoma (IGRG88, 93, 121) xenografts treated at an advanced stage of tumor growth in comparison with that of doxorubicin. Animals were randomly assigned to receive i.v. S16020 or doxorubicin weekly for three consecutive weeks. The optimal dose was 80 mg/kg per week. S16020 demonstrated a significant antitumor activity in two out of three medulloblastoma xenografts. IGRM57 xenografts were highly sensitive with 100% tumor regressions and a tumor growth delay (TGD) of 102 days, while one of eight IGRM34 xenografts showed a partial regression with a TGD of 16 days. Doxorubicin was significantly more active than S16020 in these two models. IGRM33, a model established from a tumor in relapse after chemotherapy and radiotherapy, was refractory to both drugs. S16020 demonstrated a significant antitumor activity in the three glioblastoma xenografts evaluated. The wild-type p53 IGRG93 xenograft was highly sensitive with 100% tumor regressions and a TGD of 54 days. IGRG121 (wt p53) and IGRG88 (mutant p53) were moderately sensitive with TGDs of 33 and 23 days, respectively. Doxorubicin showed greater activity in two of these models. All six xenografts exhibited low expression of mdr1 as quantitated by RT-PCR, and no correlation was found with the activity of either drug. Conversely, a low activity of the two drugs was significantly associated with a high expression of MRP1 in medulloblastomas. Finally, no relationship was observed between drug sensitivity to either drug and expression of their target, topoisomerase IIalpha. In conclusion, S16020 and doxorubicin showed significant antitumor activity in brain tumor xenografts treated at an advanced stage of tumor growth. Their activity was related to MRP1 expression in medulloblastomas.

Medulloblastoma in a cat: clinical and MRI findings

A two-year-old, castrated crossbred cat presented with loss of balance and anorexia. A mass of the caudal aspect of the cerebellum was revealed by magnetic resonance imaging (MRI). The mass was hypointense on T1-weighted images, iso- and hyperintense on T2-weighted images and was enhanced by intravenous gadolinium contrast medium. The MRI characteristics of this case were similar to those of medulloblastoma of the cerebellar vermis in humans. The authors were able to remove almost all of the tumour. The cat was discharged from hospital on day 22 after surgery, but died on day 45. The excised tissue was histologically diagnosed as medulloblastoma.

Cerebellar myxoid type meningioma in a Shih Tzu dog

A 6-year and 9 month-old, male, Shih Tzu dog showed ataxia and trembling. By MRI examination, a mass (1 cm) was found in the right cerebellum. As the dog did not respond to radiation therapy, and showed a rise of intracranial pressure, he was euthanized. The cerebellar mass was soft and hemorrhagic. Histologically, the mass contained vimentin-positive spindle- or polyhedral-shaped cells arranged in a cord-like pattern. Mucinous materials were observed in the intercellular spaces. Ultrastructural examination revealed cell processes, microtubule-like structures and desmosomes. The case was diagnosed as myxoid type meningioma.

Primary T-cell lymphoma of the central nervous system in a dog

Primary T-cell lymphoma is a rare form of CNS neoplasia. Diagnosis may be aided by use of cytologic examination of CSF. Primary CNS T-cell lymphoma should be considered in a patient with multiple cranial nerve abnormalities, even if results of imaging studies are considered normal.

Cerebellar cystic meningioma in a dog

A 21-kg, seven-year-old, male, mixed-breed Labrador retriever was admitted for incoordination and a head tilt of approximately three months' duration. Ataxia was noted of the trunk and limbs, and there was a head tilt to the right side. Conscious proprioceptive deficits were present in the left thoracic and pelvic limbs (i.e., hemiparesis). These abnormalities were consistent with paradoxical vestibular syndrome and a lesion involving the caudal cerebellar peduncle. A mass lesion consisting primarily of fluid was present on magnetic resonance imaging and at craniectomy. Histopathological diagnosis was a cystic meningioma. Based upon previous reports and experience, the location of this tumor was unusual.

Cerebellar medulloblastoma with multiple differentiation in a dog

A 4-year-old female, spayed Border Collie Dog was brought to the Veterinary Medical Teaching Hospital for evaluation of a progressive head tilt and ataxia that were unresponsive to therapy. Neurologic examination localized a right-sided lesion. The owner refused additional diagnostic tests, and necropsy was performed after euthanasia. Gross findings included atrophy of the temporal muscles and a moderately well delineated, 2.5- x 1.5- x 1.0-cm, gray soft-tissue mass compressing the right cerebellar hemisphere and dorsal hindbrain, resulting in massive dilatation of the lateral, third, and fourth ventricles and hydrocephalus. Histologic examination revealed two distinct features: undifferentiated, primitive, polygonal to fusiform cells with typical morphologic characteristics of medulloblastoma and interspersed areas containing myelinated axons and cells with glial and neuronal differentiation. Immunohistochemical examination confirmed the presence of primitive neuroepithelium and cells with glial and neuronal differentiation.

Ataxia associated with lymphosarcoma in a dog

A 4-year-old English Springer Spaniel with ataxia was examined because of progression of neurologic signs. Complete physical examination and results of CBC and serum biochemical analysis revealed no other abnormalities. The dog developed respiratory arrest and was euthanatized during recovery from general anesthesia, which had been performed to obtain a CSF sample. Results of CSF analysis were within reference limits. Necropsy revealed a single, well-circumscribed mass in the cerebellum, which was diagnosed as lymphosarcoma. The dog had no peripheral lymphadenopathy or organomegaly suggestive of the generalized form of the disease.

Epithelioma of the fourth ventricle in a goat

We describe an epithelial neoplasm arising from the fourth ventricle of a goat and extending into the subjacent cerebellum along the spaces of Virchow-Robin. The neoplastic cells are consistent with squamous epithelium based upon light microscopic morphology and cytokeratin immunoreactivity. The lack of overt keratin formation and the lack of an exophytic component distinguishes this neoplasm from intracranial epidermoid cysts, resulting in the classification of this caprine tumor as an epithelioma.

Intracranial meningioma with pulmonary metastasis in three dogs

Extracranial metastasis of primary central nervous system neoplasms is uncommon and has not been described in the dog. We report the clincopathologic features of intracranial meningioma with pulmonary metastasis in three dogs (case No. 1: 13-year-old castrated male Boxer dog; case No. 2: 14-year-old spayed female Dachshund; case No. 3: 6-year-old spayed female German Shepherd Dog). Case No. 1 presented with ataxia, lethargy, vomiting, and leaning and falling to the right, and had a transient remission following radiation and corticosteroid therapy; case No. 2 had a history of seizures that were unresponsive to primidone, left-sided postural reaction deficits, ataxia, and circling to the right; case No. 3 had only intermittent episodes of vomiting Computed tomography of case Nos. 1 and 2 revealed peripherally located homogeneous contrast-enhancing intracranial masses. Postmortem examination revealed intracranial masses with single or multiple pulmonary nodules in all three cases. Histologically, the intracranial and pulmonary masses were meningotheliomatous meningiomas with atypical features including brain infiltration, necrosis, nuclear atypia, prominent nucleoli, and moderate cell density. All of the primary meningiomas had low mitotic rates. The current interest in early diagnosis and aggressive clinical/surgical management of canine patients with meningioma and other primary central nervous system neoplasms will likely result in an increased detection of extracranial metastases.

Vestibular syndrome associated with an ependymoma in a cat

An ependymoma was diagnosed in a 4.5-year-old spayed Siamese cat with clinical signs of vestibular disease. Diagnosis was based on history, results of neurologic examination, and the finding of neoplastic cells in CSF. Necropsy revealed an ependymoma arising from the fourth ventricle of the ventricular CNS and involving the left medullary and cerebellar areas.

Intracranial dermoid cyst in a dog

A 7-year-old spayed bitch had a 3-year history of episodes of hind-limb weakness and ataxia. Neurologic abnormalities consisted of deficits in postural reactions, spinal reflexes, and conscious proprioception. A right-sided head tilt also was observed. Immediately after cervical radiography, CSF tap, and electroencephalography, the dog was alert, but it was found comatose the next morning and died within an hour. At necropsy, a 1.6- x 0.8- x 1.5-cm, thinly encapsulated mass was found on the left cerebellar peduncle. It had caused dorsal displacement of the left portion of the cerebellum and ventral compression of the fourth ventricle. Histologically, the mass was determined to be a dermoid cyst.

A medulloblastoma in a baboon (Papio papio)

A transitional medulloblastoma was found in the cerebellum of a young female baboon. The primary lesion that permitted its discovery was papillary and retinal edema in the peripapillary zone.

Medulloblastoma in calves. A report of three cases

Three calves with a history of neurological disturbances suggesting cerebellar dysfunction were submitted for necropsy. In each case a tumour was found attached to, and continuous with, the anterior cerebellum. Histologically all were medulloblastomas.