Immunohistochemical features of a feline spinal cord gemistocytic astrocytoma

Case report: Surgical treatment of an astrocytoma in the thoracic spinal cord of a cat

A 15-year-old spayed female domestic shorthaired cat was evaluated for chronic progressive paraparesis and proprioceptive ataxia. Neurological examination was consistent with a T3-L3 myelopathy. Plain thoracolumbar vertebral column radiographs and CT without intravenous contrast or myelography performed at another facility did not highlight any abnormalities. MRI of the thoracolumbar spinal cord identified an intraparenchymal space-occupying lesion extending from T10-T12. Surgery was performed to remove as much of the mass as possible, and to submit samples for histopathology. A dorsal laminectomy was performed over T9-T13. A midline myelotomy provided access to the mass, which was debrided with an intraoperative estimate of 80% removal. Histopathologic examination was consistent with a diagnosis of an astrocytoma. Post-operative treatment consisted of amoxicillin clavulanic acid, prednisolone, gabapentin, and additional analgesic medications in the direct post-operative period. Over the following 4 months, slow recovery of motor function was seen with continued physiotherapy. During the following 2 months, renal and cardiopulmonary disease were diagnosed and treated by other veterinarians. The cat was also reported to have lost voluntary movement in the pelvic limbs during this period, suggesting regression to paraplegia. Finally, 6 months post-surgery, the owner elected humane euthanasia. This is the second documentation of surgical treatment and outcome of an astrocytoma in the spinal cord of a cat.

A Scoping Review on Tyrosine Kinase Inhibitors in Cats: Current Evidence and Future Directions

Tyrosine kinase inhibitors (TKIs) have become invaluable in the treatment of human and canine malignancies, but their role in feline oncology is less defined. While toceranib phosphate and masitinib mesylate are licensed for use in dogs, no TKI is yet approved for cats. This review systematically maps the research conducted on the expression of tyrosine kinases in neoplastic and non-neoplastic domestic feline tissues, as well as the in vitro/in vivo use of TKIs in domestic cats. We identify and discuss knowledge gaps and speculate on the further research and potential indications for TKI use in cats. A comprehensive search of three electronic databases and relevant paper reference lists identified 139 studies meeting the inclusion criteria. The most commonly identified tumors were mast cell tumors (MCTs), mammary and squamous cell carcinomas and injection-site sarcomas. Based on the current literature, toceranib phosphate appears to be the most efficacious TKI in cats, especially against MCTs. Exploring the clinical use of TKIs in mammary carcinomas holds promise. Despite the progress, currently, the evidence falls short, underscoring the need for further research to discover new indications in feline oncology and to bridge the knowledge gaps between human and feline medicine.

Unique cytologic and imaging features of a lumbosacral oligodendroglioma in a cat

A 12-y-old castrated male domestic longhaired cat had progressive paraparesis and neurolocalization of L4-S3. MRI revealed a circumscribed intradural-extraparenchymal mass from L5 to S1 that was T2 and short tau inversion recovery hyperintense and strongly contrast-enhancing. Cytologic interpretation of a blind fine-needle aspirate obtained through the L5-L6 space was a tumor of probable mesenchymal origin. A pair of suspect neoplastic cells was seen on a cytocentrifuged preparation of the atlanto-occipital CSF sample, despite a normal nucleated cell count (0 × 106/L) and total protein (0.11 g/L) with only 3 RBCs × 106/L. Clinical signs progressed despite increasing doses of prednisolone and cytarabine arabinoside. Repeat MRI on day 162 demonstrated tumor progression from L4 to Cd2 vertebral segments with intraparenchymal extension. Surgical tumor debulking was attempted, but an L4-S1 dorsal laminectomy revealed diffusely abnormal neuroparenchyma. Intraoperative cryosection favored lymphoma, and the cat was euthanized intraoperatively 163 d following presentation. Postmortem examination was performed, and the final diagnosis was a high-grade oligodendroglioma. This case illustrates the cytologic, cryosection, and MRI features of a unique clinical presentation of oligodendroglioma.

A review of primary central nervous system neoplasms of cats

Primary central nervous system (CNS) neoplasms are uncommonly diagnosed in cats. The majority of primary feline CNS neoplasms described in the veterinary literature consist of meningioma and glioma occurring mainly in the brain and less often in the spinal cord. Although most neoplasms can be diagnosed based on routine histologic evaluation, less typical tumors need to be further characterized using immunohistochemistry. This review compiles the relevant information about the most common primary CNS neoplasms of cats available in the veterinary literature, aiming to serve as a converging source of information for the topic.

Diagnosis and clinical outcome following surgical resection of an intracranial grade III anaplastic gemistocytic astrocytoma in a cat

CASE SUMMARY

A 10-year-old Maine Coon cat was presented for acute onset seizures and cerebrothalamic signs. An intracranial mass, suspected to be a meningioma, was diagnosed on MRI and surgically excised. Histopathology appeared consistent with an atypical meningioma. However, following rapid regrowth of the neoplasm, the patient was humanely euthanized 3 months later. On post-mortem histopathology, the neoplasm was diagnosed as a grade III anaplastic gemistocytic astrocytoma.

RELEVANCE AND NOVEL INFORMATION

Gemistocytic astrocytomas are rare brain tumors in the feline patient. This case represents the first report of a feline grade III anaplastic gemistocytic astrocytoma in the cerebrum of a cat with surgical excision and recurrence. The challenging nature of ante-mortem diagnosis and the guarded prognosis, despite surgical intervention, are presented in this report.

Feline glioma: a retrospective study and review of the literature

Case series summary This study aimed to evaluate the pathologic and diagnostic features of 13 cases of feline glioma diagnosed at two veterinary diagnostic institutions over 16 years. A retrospective search was conducted using the laboratory information system. Selected cases were reviewed, tumors were classified according to the 2007 World Health Organization Classification of Tumours of the Central Nervous System, and tissue sections were submitted to an immunohistochemistry panel for further characterization. Affected cats were adults (average age 8 years), and male neutered (9/13) domestic shorthair cats (12/13) were over-represented. Clinical signs had acute onset and were progressive, lasting from 1-60 days (average course 20.7 days). Euthanasia was elected in all but one case, owing to a poor prognosis or because of a suspicion of rabies. Tumors occurred in the telencephalon (8/13), spinal cord (3/13) and brainstem (2/13). Gross changes in seven cases consisted of well- or poorly demarcated, gray-to-brown, soft, gelatinous masses that often caused secondary changes to the brain. The final diagnosis and classification were made based on histopathology and immunohistochemistry. Diagnoses consisted of oligodendroglioma (six cases), anaplastic astrocytoma (two cases), oligoastrocytoma, anaplastic ependymoma, gliomatosis cerebri, glioblastoma and anaplastic oligodendroglioma (one case each). Relevance and novel information This article confirms the need for a full neurologic and neuropathologic examination in cats with clinical neurologic disease. In addition, it highlights and proposes a complete routine immunohistochemical panel for diagnostic confirmation and differentiation between glioma and other morphologically similar central nervous system neoplasms in cats.

Diagnostic immunohistochemistry of canine and feline intracalvarial tumors in the age of brain biopsies

The focus of immunohistochemistry as applied to nervous system tumors is in identifying the neoplasm present and evaluating margins between normal and neoplastic tissue. Although not always utilized by specialists in neuropathology, immunohistochemistry remains useful to resolve concerns about the differentiation and rate of tumor growth. The aims of this review are to discuss the utility of immunohistochemical reagents currently used in diagnosis of canine and feline intracalvarial tumors, to indicate the applicability of some tests currently used in human nervous system tumors for domestic species, and to evaluate a few less commonly used reagents. A panel of biomarkers is usually needed to confirm a diagnosis, with groups of reagents for leptomeningeal, intraparenchymal, and ventricular neoplasms. In the future, signature genetic alterations found among feline and canine brain tumors--as correlated prospectively with diagnosis, rate of enlargement, or response to treatment--may result in new immunohistochemical reagents to simplify the task of diagnosis. Prospective studies determining the type and proportion of stem cell marker expression on patient longevity are likely to be fruitful and suggest new therapies. Due to increased frequency of biopsy or partial resection of tumors from the living patient, biomarkers are needed to serve as accurate prognostic indicators and assist in determining the efficacy of developing therapeutic options in nervous system tumors of dogs and cats.

Long-term follow-up of surgical treatment of spinal anaplastic astrocytoma in a cat

A 10-year-old spayed female chinchilla feline presented with gradually progressive tetraparesis and cervical pain that had begun 1 month before the onset of a 4-day tetraplegic episode. Magnetic resonance imaging revealed a large elliptical intramedullary mass at the fourth cervical vertebrae. The mass was removed surgically and diagnosed as an anaplastic astrocytoma. No neurological abnormalities were observed 3 weeks postsurgery. Magnetic resonance at 3.5 year follow-up revealed neither mass regrowth nor recurrence of signs.