Pathological and immunohistochemical features of 45 cases of feline meningioma

Magnetic resonance and computed tomographic imaging characteristics and potential molecular mechanisms of feline meningioma associated calvarial hyperostosis

Meningiomas are the most common feline primary brain tumours, and calvarial hyperostosis (CH) is frequently documented in association with this neoplastic entity. The clinical significance of and mechanisms driving the formation of CH in cats with meningiomas are poorly understood, although tumour invasion into the skull and tumour production of cytokines and enzymes have been implicated as causes of CH in humans. This retrospective study investigated relationships between signalment, MRI or CT imaging features, histopathologic tumour characteristics, alkaline phosphatase (ALP) isoenzyme concentrations, tumour expression of matrix metalloproteinases (MMP)-2, MMP-9, and interleukin-6 (IL-6), and progression free survival times (PFS) following surgical treatment in 27 cats with meningiomas with (n = 15) or without (n = 12) evidence of CH. No significant differences in breed, age, sex, body weight, tumour grade, tumour volume, peritumoral edema burden, ALP isoenzyme concentrations, tumour Ki-67 labelling indices or MMP-2 or MMP-9 expression and activity, or PFS were noted between cats with or without CH. There was a trend towards higher serum (p = .06) and intratumoral (p = .07) concentrations of IL-6 in cats with CH, but these comparisons were not statistically significant. Histologic evidence of tumour invasion into bone was observed in 5/12 (42%) with CH and in no (0/6) cats without CH, although this was not statistically significant (p = .07). Tumour invasion into bone and tumour production of IL-6 may contribute to the formation of meningioma associated CH in cats, although larger studies are required to further substantiate these findings and determine their clinical relevance.

Monoclonal antibody cetuximab impairs matrix metalloproteinases 2 and 9, epithelial-mesenchymal transition and cell migration in feline oral squamous cell carcinoma in vitro

Feline oral squamous cell carcinoma (FOSCC) is characterised by invasive and metastatic behaviour and is poorly responsive to current treatments, hence the need for new therapeutic strategies. FOSCC shares molecular targets with human head and neck squamous cell carcinoma (HNSCC), among these the epidermal growth factor receptor. Cetuximab is an anti-epidermal growth factor receptor monoclonal antibody employed in the therapy of HNSCC and, interestingly, previous work in vitro suggested that it displays cytostatic and cytotoxic properties also against FOSCC. With the present study, we aimed at further investigating the effects of cetuximab on invasion and metastasis pathways proven to be relevant in human patients. To this purpose, FOSCC cell lines SCCF1, SCCF2 and SCCF3 were treated with cetuximab for 48/72 h and subjected to Western blot for matrix metalloproteinases-2/9 (MMP-2/9) and epithelial-mesenchymal transition markers vimentin, E-, P- and N-cadherin. Treatment with cetuximab resulted in downregulation of MMP-2/-9 in all of the three cell lines in a dose-dependent manner. Moreover, cetuximab downregulated vimentin and P-cadherin in SCCF1, upregulated E-cadherin whilst downregulating P-/N-cadherins in SCCF2, and impaired P-/N-cadherins in SCCF3. An in vitro scratch test also demonstrated that cetuximab delayed cell migration in SCCF3. These data suggest that cetuximab mitigates invasion and metastasis processes by impairing MMPs and epithelial-mesenchymal transition pathways in FOSCC, indicating that this monoclonal antibody may help to counteract malignant progression and improve the management of locally invasive disease.

Surgical treatment of feline intracranial meningiomas: a retrospective study of 26 cases

BACKGROUND

Surgical excision is the treatment of choice for feline intracranial meningioma.

OBJECTIVES

To report clinical findings, complications, and outcomes following surgery for feline intracranial meningioma.

METHODS

Medical records (01/2000-01/2017) of cats that underwent surgical excision of an intracranial meningioma at our institution were reviewed. Patient data included signalment, clinical signs, surgical technique, complications, histopathologic diagnosis, survival time, and owners' answers to a satisfaction questionnaire. Survival was assessed using the Kaplan-Meier method and log-rank test.

RESULTS

Twenty-six cats were included in this study. The exact cause of death was known in 17 cases and was not related to meningioma in 9/17 cases. Overall median survival time was 881 days (95% confidence interval 518; 1248). The age of the cat did not influence survival (p = 0.94) or the occurrence of complications (p = 0.051). Complications occurred in 13/24 cats, including dramatic complications in 4/24 cats. Most complications appeared in the first 24 hours post-surgery (12/13). Males had more postoperative complications (p = 0.042), including more seizures (p = 0.016). Cats with cranioplasty had fewer complications (p = 0.021). Clinical recurrence was confirmed in 3 out of 17 cats. Recurrence-free survival time was 826 days. Most owners (12/14) were satisfied with the outcome.

CONCLUSIONS

Surgical treatment of intracranial meningioma in cats was associated with a long median survival time but also with a high rate of minor and major postoperative complications, including early postoperative seizures. Cranioplasty may reduce complications. Age at the time of surgery had no effect on outcomes.

Diagnostic immunohistochemistry of primary and secondary central nervous system neoplasms of dogs and cats

The diagnosis of primary and secondary CNS neoplasms of dogs and cats relies on histologic examination of autopsy or biopsy samples. In addition, many neoplasms must be further characterized by immunohistochemistry (IHC) for a more refined diagnosis in specific cases. Given the many investigations assessing the diagnostic and prognostic IHC profile of CNS neoplasms in the veterinary literature, it may be difficult for the diagnostic pathologist or pathology trainee to narrow the list of reliable diagnostic IHCs when facing a challenging case. Here we compile a comprehensive list of the most diagnostically relevant immunomarkers that should be utilized for the diagnostic support or confirmation of the most common primary and secondary CNS neoplasms of dogs and cats.

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.

The expression of platelet-derived growth factor and its receptor in canine and feline meningiomas

Feline meningiomas usually have benign biological behavior, while canine and human meningiomas are often classified as grade 2 or 3. Activation of the platelet-derived growth factor (PDGF) and its receptor signal pathway through PDGFβ/Rβ autocrine and paracrine is considered to play an important role in the tumor proliferation and malignant transformation of human meningiomas. However, there have been few studies about the expression of these molecules in canine meningiomas and no studies about their expression in feline meningiomas. We analyzed the PDGFα/Rα and PDGFβ/Rβ expression in canine and feline meningiomas by immunohistochemistry and western blotting. Immunohistochemically, most canine meningiomas showed the expression of PDGFα (42/44; 95.5%), PDGFRα (44/44; 100%) and PDGFRβ (35/44; 79.5%), and a few showed the expression of PDGFβ (8/44; 18.2%). In contrast, feline meningiomas were immunopositive for PDGFRα and PDGFRβ in all cases (14/14; 100%), while no or a few cases expressed PDGFα (0/14; 0%) and PDGFβ (2/14; 14.3%). Western blotting revealed specific bands for PDGFα, PDGFRα and PDGFRβ, but not for PDGFβ in a canine meningioma. In a feline meningioma, specific bands for PDGFRα and PDGFRβ were detected, but not for PDGFα and PDGFβ. These results suggested that canine meningiomas commonly express PDGFα/Rα, and thus autocrine or paracrine PDGFα/Rα signaling may be involved in their initiation and progression. Moreover, PDGF negativity may be related to benign biological behavior and a low histopathological grade in feline meningioma.

Meningothelial hamartoma on the forehead of a young cat

A 1 year and 2-months-old neutered male cat underwent surgical resection of a cutaneous nodule on the midline of the forehead that had been present since approximately 6 months of age. Histopathologically, the nodule was composed of interlacing collagenous fibres interspersed with varying numbers of spindloid cells with round to oval nuclei and moderate to abundant amounts of pale eosinophilic cytoplasm. Similar to meningothelial cells, the spindloid cells were immunopositive for vimentin, neuron-specific enolase, E-cadherin and somatostatin receptor 2. Based on these findings and the absence of nuclear atypia and mitotic figures, the nodule was diagnosed as meningothelial hamartoma. Although cases of cutaneous meningioma have been reported, this is the first report of meningothelial hamartoma in a domestic animal.

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.

Epithelial membrane antigen-reactive feline chordoid meningioma in a European wildcat (Felis silvestris)

Meningioma is the most frequent intracranial neoplasm in cats. Here we describe the first case of chordoid meningioma (CM), a rare grade II meningioma subtype, in a 5.5-year-old European wildcat (Felis silvestris) from a Swiss zoo. The wildcat was found dead after a clinical history of neurological signs and clinical suspicion of a carcinoma in the right external ear canal with concurrent chronic otitis. Post-mortem examination revealed a large intracranial, extra-axial and intradural neoplasm that invaded into the right ear canal and had histological features compatible with CM, which has been only reported in humans and dogs. Neoplastic cells expressed vimentin but were negative for glial fibrillary acidic protein, S100 and pancytokeratin. Immunohistochemistry revealed epithelial membrane antigen (EMA) expression in neoplastic cells. To the best of our knowledge, we provide the first evidence of EMA expression in feline meningioma.

Neurosurgery in feline epilepsy, including clinicopathology of feline epilepsy syndromes

Feline epilepsy is treated with antiseizure medications, which achieves fair to good seizure control. However, a small subset of feline patients with drug-resistant epilepsy requires alternative therapies. Furthermore, approximately 50 % of cats with epileptic seizures are diagnosed with structural epilepsy with or without hippocampal abnormality and may respond to surgical intervention. The presence of hippocampal pathology and intracranial tumors is a key point to consider for surgical treatment. This review describes feline epilepsy syndrome and epilepsy-related pathology, and discusses the indications for and availability of neurosurgery, including lesionectomy, temporal lobectomy with hippocampectomy, and corpus callosotomy, for cats with different epilepsy types.

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.