MRI ischemic and hemorrhagic lesions in arterial and venous territories characterize central nervous system intravascular lymphoma in dogs.

Intravascular lymphoma (IVL) is characterized by the proliferation of large malignant lymphocytes within the lumen of blood vessels. This retrospective, multi-center, case series study aimed to describe the MRI features of confirmed central nervous system IVL in dogs and compare them with histopathological findings. Medical record databases from seven veterinary centers were searched for cases of histologically confirmed IVL. Dogs were included if an MRI was performed. The MRI studies and histopathology samples were reviewed to compare the MRI changes with the histopathological findings. Twelve dogs met the inclusion criteria (12 brains and three spinal cords). Imaging of the brains revealed multifocal T2-weighted/FLAIR hyperintense and T1-weighted iso-hypointense lesions, with variable contrast enhancement; areas of abnormal diffusion both in arterial and venous territories in diffusion-weighted imaging; and meningeal enhancement. On gradient echo images (GRE), the changes comprised tubular susceptibility artifacts, consistent with the "susceptibility vessel sign", and additional variably sized/shaped intraparenchymal susceptibility artifacts. Spinal cord lesions presented as fusiform T2-weighted hyperintensities with scattered susceptibility artifacts on GRE and variable parenchymal and meningeal contrast enhancement. On histopathology, subarachnoid hemorrhages and neuroparenchymal areas of edema and necrosis, with or without hemorrhage, indicating ischemic and hemorrhagic infarctions, were found. These lesions were concurrent with severely dilated meningeal and parenchymal arteries and veins plugged by neoplastic lymphocytes and fibrin. Due to the unique angiocentric distribution of IVL, ischemic and hemorrhagic infarcts of variable chronicity affecting both the arterial and venous territories associated with thrombi formation can be detected on MRI.

Malignant Nerve Sheath Tumor of the Hypoglossal Nerve in a Maltese Dog.

A 4 yr old male Maltese dog presented with a 1 wk history of intermittent neck pain and progressive difficulty walking. Neurologic evaluation was consistent with a left-sided brainstem lesion. On oral examination, left lingual hemiatrophy was evident suggesting hypoglossal nerve involvement. A dumbbell-shaped extra-axial mass in the left side of the caudal fossa extending extracranially through the hypoglossal canal was detected by MRI. At postmortem histologic examination, the hypoglossal nerve was diffusely infiltrated by fusiform neoplastic cells arranged in Antoni A and Antoni B patterns. This is the first description of a malignant nerve sheath tumor selectively involving the hypoglossal nerve in a dog.

Severe, diffuse fibrinonecrotic pleuropneumonia in a cat affected by multiple viral infection.

This communication describes the coinfection with feline panleukopenia virus (FPV), feline herpesvirus 1 (FeHV-1), feline calicivirus (FCV) and feline coronavirus (FCoV) in a 1 year­old domestic cat living in a feline shelter. The cat was referred to veterinary hospital with clinical signs related to diffuse gastro-intestinal inflammation, it had developed a severe pneumopathy with fibrinous exudation in all body cavities and died 8 days after initial presentation. Pathological findings and biomolecular diagnostic test results were compatible with an initial FPV infection that, in consequence of the lymphoid depletion, has fostered coinfection or reactivation of chronic-latent infections with FeHV-1, FCV, and FCoV. In the reported case, the simultaneous presence of different viruses exacerbated the clinical status of the host, resulting in multiple organ damage and leading it to its death.

Changes in electromyography and F wave responses in two cats with presumed local tetanus: implications for diagnosis and prognosis.

Two cases of focal tetanus in the cat are described. Clinical findings included severe muscular spasms of the pelvic limbs in one cat, and involvement of the thoracic limbs and muscles of the neck and face in the other. Electromyography in both cats showed spontaneous activity characterised by the presence of motor unit potentials. F waves, never previously reported in focal tetanus in animals, showed significantly increased F/M amplitude ratio in both cats and increased F wave duration in one cat. The electrodiagnostic findings provided relevant diagnostic and, possibly, prognostic information.

A case of feline neurolymphomatosis: pathological and molecular investigations.

Neurolymphomatosis is a very rare form of nervous system infiltration by lymphoma that can affect cranial and peripheral nerves and spinal nerve roots. The clinical appearance can mimic autoimmune or paraneoplastic neuropathies. To date, only 2 cases of neurolymphomatosis have been reported in the veterinary literature (1 dog and 1 cat). A case of neurolymphomatosis in a 5-year-old female Domestic Shorthair cat is reported. Two, whitish, bosselated, non-symmetric masses (1 cm × 1.2 cm × 0.5 cm) that incorporated almost all cranial nerves and semilunar ganglia occupying the basisphenoid depression were histologically composed of a proliferation of monomorphic lymphocytes. These lymphoid cells were positive for CD3 (T-cell lymphoma). Nested polymerase chain reaction detected feline leukemia provirus. Fragment analysis of feline T-cell receptor (TCR) gene rearrangements evidenced an oligoclonal pattern with few peaks of similar height. The integration of pathologic with biomolecular findings adds to the information concerning the role of Feline leukemia virus on TCRγ rearrangements in cases of feline lymphoma.