First report of the simultaneous occurrence of choroid plexus papilloma and meningioma in a dog

Clinical, magnetic resonance imaging, and histological description of a choroid plexus papilloma with disseminated intraventricular and spinal cerebrospinal fluid drop metastases in a young adult dog: a case report

A 2-year-old male entire Cane Corso was presented for investigations into a 1-week history of ambulatory paraparesis and pelvic limb ataxia gradually deteriorating. Magnetic resonance imaging (MRI) revealed intraventricular space-occupying lesions affecting the fourth ventricle and lateral apertures and intradural-extramedullary space-occupying lesions at the level of C7 vertebra, L4-L5, and L7-S1 intervertebral disk spaces. Due to poor quality of life, the patient was euthanized. A post-mortem examination revealed partially encapsulated, multifocally infiltrative, and moderately cellular neoplastic masses. The histological description was similar for all masses. The cells appeared cuboidal with round central nuclei and a moderate amount of eosinophilic cytoplasm and were arranged almost exclusively in single-layered papilliform patterns supported by a fibrovascular stroma. Mitoses were rarely observed (1/2.37 mm2). The primary neoplasm was morphologically most consistent with a choroid plexus papilloma despite drop metastases. This is the first report of a histologically confirmed primary ventricular choroid plexus papilloma causing disseminated MRI-apparent intraventricular and spinal drop metastases.

Meningioma and glioma as the first collision brain tumour reported in small animals

We describe the clinical and pathological features of a brain collision tumour consisting of a fibrous meningioma and an anaplastic oligoastrocytoma in a 14-year-old male neutered French Bulldog. Computed tomography of the brain revealed a poorly defined, intra-axial lesion affecting the left frontal lobe. Following euthanasia, histological examination showed an anaplastic oligoastrocytoma invading the brain parenchyma and an adjacent fibrous meningioma. As synchronous intracranial tumours are rare in animals, the aims of this report are to describe the clinical, imaging and histopathological features of an intracranial collision tumour in a dog and highlight the importance of a complete histopathological study despite the imaging findings.

Tumour-to-Tumour Metastasis Phenomenon: Metastatic Prostatic Adenocarcinoma within an Anaplastic Oligodendroglioma in the Brain of a Dog

A 10-year-old entire male French bulldog was presented following clusters of generalized tonic-clonic epileptic seizures. Neurolocalization was consistent with a lesion in the left forebrain. Magnetic resonance imaging of the brain revealed a large, ill-defined, intra-axial, space-occupying lesion at the level of the left temporal and parietal lobes, causing marked compression of the adjacent parenchyma. Computed tomography of the thorax and abdomen was consistent with disseminated metastatic disease. The dog was humanely destroyed and subjected to necropsy examination. Histological examination of the brain revealed a metastasis of prostatic carcinoma within an anaplastic oligodendroglioma in the left forebrain. To the author's knowledge, this is the first report describing clinical, imaging and histopathological features of an intracranial tumour-to-tumour metastasis in the brain of a dog.

Magnetic resonance imaging diagnosis of brain tumors in dogs

A great deal of information is now available regarding the range of magnetic resonance imaging (MRI) features of many primary and secondary brain tumors from dogs. In this review, these canine neoplasms are grouped into meningeal masses, ventricular masses, intra-axial enhancing lesions, intra-axial mildly to non-enhancing lesions, and multifocal lesions. For each of these patterns, the major and sporadic neoplastic differential diagnoses are provided, and guidance on how to rank differential diagnoses for each individual patient is presented. The implication of MRI features such as contrast-enhancement, signal intensities and location is discussed. However, the information garnered from MRI must be correlated with all available clinical information and with epidemiological data before creating a differential diagnosis.