Cerebral Cavernous Hemangioma in a Dog

Abstract

Background: Cerebral cavernous hemangioma is a rare neoplasm of vascular origin in the brain, characterized by abnormally dilated vascular channels surrounded by endothelium without muscle or elastic fibers. Presumptive diagnosis is performed by magnetic resonance or computed tomography (CT) scanning and can be confirmed by histopathology. The prognosis of intracranial cavernous hemangioma is poor, with progression of clinical signs culminating in spontaneous death or euthanasia. The purpose of this paper is to report a case of cerebral cavernous hemangioma in a dog, presenting the clinical findings, tomographic changes, and pathological findings.

Case: This case involved a 2-year-old medium sized mixed breed female dog presenting with apathy, hyporexia, ataxia, bradycardia, dyspnea, and seizure episodes for three days. Hemogram and serum biochemistry of renal and hepatic function and urinalysis did not reveal any visible changes. CT scanning was also performed. The scans revealed a hyperdense nodule of 15.9 x 14 mm, with well defined borders, and a hypodense halo without post-contrast enhancement and mass effect in the right parietal lobe was observed in both transverse and coronal sections. Based on the image presented in the CT scans, the nodule was defined as a hemorrhagic brain lesion. The animal died after a seizure. The right telencephalon was subjected to necropsy, which revealed a reddish-black wel-defined nodule 1.7 cm in diameter extending from the height of the piriform lobe to the olfactory trine at the groove level and extending towards the lateral ventricle, with slight compression and deformation of the thalamus but no other macroscopic alterations in the other organs. The histopathology indicated that this nodular area in the encephalus contained moderate, well-delimited but unencapsulated cellularity, composed of large vascular spaces paved with endothelial cells filled with erythrocytes, some containing eosinophilic fibrillar material (fibrin) and others with organized thrombus containing occasional neutrophil aggregates. The endothelial cells had cytoplasm with indistinct borders, elongated nuclei, scanty crust-like chromatin, and cellular pleomorphism ranging from discrete to moderate, without mitotic figures.

Discussion: The histological findings characterized the morphological changes in the brain as cavernous hemangioma, and the growth and compression of this neoplasm were considered the cause of the clinical signs of this dog. The main complaint was seizures, although ataxia and lethargy were also noted. These clinical signs are often related to changes in the anterior brain and brainstem. The literature does not list computed tomography as a complementary diagnostic method in cases of cerebral cavernous hemangioma in dogs, but CT scanning was useful in confirming cerebral hemorrhage. The main differential diagnosis for cerebral cavernous hemangioma would be a hamartoma, but what differentiates them histologically is the presence of normal interstices between the blood vessels, since no intervening neural tissue occurs in the case of cerebral hemangioma. Therefore, even in the absence of immunohistochemistry to more confidently confirm a cavernous hemangioma, the clinical signs, CT scans and especially the pathological findings were consistent with a case of cerebral cavernous hemangioma, a benign neoplasm with a poor prognosis due to the severe neurological changes it causes and its difficult treatment.