Vet. World, 2012, Vol.5(8):495-498 CLINICAL Multiple meningiomas in a dog: a case report

Introduction was delayed, worse on the left side and in the pelvic limbs. Mentation was appropriate, and cranial nerve Meningioma is a common intracranial tumor examination was within normal limits. The segmental encountered in dogs and cats [1,2], and represents reflexes were also within normal limits. A neuroapproximately 30 to 45% of all reported canine anatomic localization was made to the cerebrum. intracranial tumors [3] Dolichocephalic dogs were In preparation for the MRI examination, the dog overrepresented in 2 studies, including German was premedicated with Oxymorphone (0.05 mg/kg) shepherd dogs, golden retrievers and boxers [1,2]. and Atropine (0.02 mg/kg) subcutaneously, followed Meningiomas are more commonly reported in middle by intravenous administration of propofol (1.5 to older age dogs [1,2]. Some articles revealed a mg/kg). The dog was intubated and anesthesia was female sex predilection [1]. Multiple meningioma is maintained with a constant rate infusion of Fentanyl common in cats representing approximately 17% of (0.5μg/kg/min) and propofol (0.2mg/kg/min). all reported feline meningiomas [4]. However it is Magnetic resonance imaging was performed using a rarely reported in dogs [2,5]. 1.5 Tesla MR unit (General Electric MR Signa LX, Case history General Electric Co., Milwaukee, WI). On precontrast T1 images, a small rounded mass like lesion measuring An 11 year old female spayed, shepherd mix dog approximately 1 cm, located at the periphery of the presented to the Veterinary Medical Teaching Hopsital right frontal lobe, was identified. This mass was slightly at UC Davis for three generalized seizures in the hyperintense to the white mater on T1 weighted previous 12 days. The dog had been diagnosed two images and hyperintense to the white matter on T2 years earlier with vertebral column plasma cell tumor weighted images. A marked hyperintense signal on T2 and had undergone a T11 decompression and and FLAIR weighted images was present surrounding stabilization procedure for the treatment of a the mass rostrally and caudally, tracking through the pathological fracture and myelopathy at that time. white matter. The T2 and FLAIR hyperintense signal Chemotherapy, consisting of melphalan and could be followed rostrally towards the region of the prednisone, was administered for the following 14 right olfactory peduncle. A mass effect was present in months until the dog developed marked thrombothe region of the primary mass with leftward deviation cytopenia. All medications were stopped and the dog of the falx cerebri and ventral compression of the remained free of neurological signs and in remission lateral ventricles (Figure-1). from the tumor. On T1 weighted images following intravenous Clinical diagnosis administration of gadopentate dimeglumine (0.1 mmol/kg, Magnevist, Bayer HealthCare PharmaceuThe physical examination was unremarkable. ticals Inc., Wayne, NJ), the mass lesion in the right Neurological examination on the day of presentation frontal lobe strongly and homogeneously contrast revealed an ambulatory patient with generalized enhanced. A second smaller extra-axial mass was ataxia and tetraparesis. Proprioceptive positioning Vet. World, 2012, Vol.5(8):495-498 CLINICAL


Introduction
was delayed, worse on the left side and in the pelvic limbs.Mentation was appropriate, and cranial nerve Meningioma is a common intracranial tumor examination was within normal limits.The segmental encountered in dogs and cats [1,2], and represents reflexes were also within normal limits.A neuroapproximately 30 to 45% of all reported canine anatomic localization was made to the cerebrum.intracranial tumors [3] Dolichocephalic dogs were In preparation for the MRI examination, the dog overrepresented in 2 studies, including German was premedicated with Oxymorphone (0.05 mg/kg) shepherd dogs, golden retrievers and boxers [1,2].
and Atropine (0.02 mg/kg) subcutaneously, followed Meningiomas are more commonly reported in middle by intravenous administration of propofol (1.5 to older age dogs [1,2].Some articles revealed a mg/kg).The dog was intubated and anesthesia was female sex predilection [1].Multiple meningioma is maintained with a constant rate infusion of Fentanyl common in cats representing approximately 17% of (0.5µg/kg/min) and propofol (0.2mg/kg/min).all reported feline meningiomas [4].However it is Magnetic resonance imaging was performed using a rarely reported in dogs [2,5].
1.5 Tesla MR unit (General Electric MR Signa LX,

Case history
General Electric Co., Milwaukee, WI).On precontrast T1 images, a small rounded mass like lesion measuring An 11 year old female spayed, shepherd mix dog approximately 1 cm, located at the periphery of the presented to the Veterinary Medical Teaching Hopsital right frontal lobe, was identified.This mass was slightly at UC Davis for three generalized seizures in the hyperintense to the white mater on T1 weighted previous 12 days.The dog had been diagnosed two images and hyperintense to the white matter on T2 years earlier with vertebral column plasma cell tumor weighted images.A marked hyperintense signal on T2 and had undergone a T11 decompression and and FLAIR weighted images was present surrounding stabilization procedure for the treatment of a the mass rostrally and caudally, tracking through the pathological fracture and myelopathy at that time.
white matter.The T2 and FLAIR hyperintense signal Chemotherapy, consisting of melphalan and could be followed rostrally towards the region of the prednisone, was administered for the following 14 right olfactory peduncle.A mass effect was present in months until the dog developed marked thrombothe region of the primary mass with leftward deviation cytopenia.All medications were stopped and the dog of the falx cerebri and ventral compression of the remained free of neurological signs and in remission lateral ventricles (Figure -1).from the tumor.
On T1 weighted images following intravenous identified in the left frontal lobe and a third mass was swelling following opening of the dura mater.Two of identified at the caudodorsal aspect of the right olfactory the tumors were surgically removed through peduncle.For each of the masses, the meninges combined transfrontal and rostrotentorial approaches contiguous with and tapering away from the mass to the brain.Mass removal was accomplished using were contrast enhancing, representing a dural tail sign.ultrasonic aspiration.Following removal, the dural The masses appeared to be separate in location.Based defect was repaired using a temporalis muscle graft on the imaging findings of multiple extra-axial obtained from the right temporalis muscle.A skull cap, masses, a tentative diagnosis of multiple meningiomas fashioned from polymethylmethacrylate, was used to was established.Other differential diagnosis included cover the bony defect in the frontal/parietal bones .a recurrence of the previous multiple myeloma, lym-The patient recovered well after the surgery and no phosarcoma, histiocytic sarcoma or dural metastases.
further seizures were noted.The histopathologic diagnosis was meningioma of mixed psammomatous Treatment and transitional subtypes.A craniotomy was performed to remove the Discussion intracranial masses on the left side (frontal lobe and olfactory bulb).The patient was positioned in sternal Multiple meningioma is a rare condition in small recumbency with the head elevated.The anesthetic animals.[2,5].In the human literature, multiple protocol used for the MRI was continued.The patient meningiomas are frequently encountered in neuroreceived an intra-operative IV bolus of mannitol fibromatosis type II.Neurofibromatosis type II is an (0.5mg/kg) during the surgery due to acute brain autosomal dominant neurocutaneous disorder which

usually develops in adult patients. It manifests as
A dural tail sign can frequently be appreciated at development of multiple central nervous system the margin of the meningioma after contrast administumors.The patients generally develop bilateral tration in dogs[2] and cats [4].On post contrast T1 vestibular schwannomas with additional intracranial, weighted images, the dural tail sign is identified as a intraspinal tumors such as meningioma, glioma and thickening of the dura adjacent to an intracranial ependymoma.These conditions have not been pathology.Also known as meningeal sign, it is recognized in dogs to date [6][7][8].
generally reported with meningioma however it is not The clinical signs associated with multiple pathognomonic for meningioma and may be meningiomas vary depending on the location, growth associated with other extra-axial pathologies such as rate and secondary effects.Seizures and decreased lymphoma, and dural metastasis [12].The pathoactivity level, as well as behavioral changes, are physiology of the dural tail sign is complex and not frequently reported.[5,9] In our patient, seizures, fully established in the human literature.Invasion of proprioceptive deficits, and generalized ataxia the dural vessels by tumor cells and packing at the correlated with the location of the masses.point of tumor attachment, reactive hypervascularity The origin of multiple meningioma is unclear, and tumoral invasion of the dura are three suspected however multiple meningiomas may represent multipathophysiologies of dural tail sign [12].centric disease or may represent local metastasis from Multiple therapeutic options are available for a single lesion.In a previous article, the multiple treatment of multiple meningiomas.The current meningeal masses were located on the same side of the treatment recommendations include surgery and/or brain.[5] In the present case the masses involved radiation therapy [13].The most appropriate choice of meninges on both sides of the brain.All the masses therapy usually depends on the localization of the were localized in the supratentorial fossa as in the masses and their biological behavior.previous case report [5].
On MRI, meningiomas are usually iso-to Conclusion hypointense compared to the gray matter on T1 In conclusion, multiple meningioma is a rare weighted images, and are hyperintense to isointense to intracranial tumor that appears to be limited to cranial the gray matter on T2 weighted images [2, 5,10,11].
and middle cranial fossa.The clinical signs, MR They usually have a broad base and rounded features, and recommended treatment are similar to a appearance and occur along the falx cerebri or the single intracranial meningioma.meninges.After contrast administration, the majority of meningiomas diffusely, strongly contrast enhance References and have sharp margins.The contrast enhancement dimeglumine (0.1 mmol/kg, Magnevist, Bayer HealthCare Pharmaceu-The physical examination was unremarkable.ticals Inc., Wayne, NJ), the mass lesion in the right Neurological examination on the day of presentation frontal lobe strongly and homogeneously contrast revealed an ambulatory patient with generalized enhanced.A second smaller extra-axial mass was ataxia and tetraparesis.Proprioceptive positioning To cite this article: Daniaux LA, Sturges BK, Zwingenberger AL (2012) Multiple meningiomas in a dog: a case report, Vet World 5(8):495-498.doi: 10.5455/vetworld.2012.495-498

Figure- 1 .
Figure-1.Transverse MR images of the brain at the level of the rostral frontal lobe.T1 weighted image (A), T1 weighted image after contrast media administration (B), T2 weighted image (C), and FLAIR weighted image (D).(A) The largest mass is visible as a slight T1 hyperintensity in the frontal lobe (white arrows), and a mass effect is shifting the falx cerebri to the left.(B) After contrast administration, the mass on the right is strongly contrast-enhancing.A second dural mass is visible in the left frontal lobe (black arrow).Well defined dural tails are visualized.(C,D) A moderate amount of hyperintense signal in the white matter (*) is present, representing edema.
Kay WJ and Hurvitz AI (1986)    pattern may vary due to the presence of cysts or Intracranial meningioma: a comparative pathologic necrosis within the meningeal mass, or mineralization study of 28 dogs.Vet Pathol 23(4): 369-373.within the tumor (i.e.psammoma bodies).On T2 and 2. Sturges BK, Dickinson PJ, Bollen AW, Koblik PD, FLAIR weighted images, a large amount of Kass PH, Kortz GD, Vernau KM, Knipe MF, hyperintense signal was noted in the white matter LeCouteur RA and Higgins RJ (2008) Magnetic surrounding the masses and represented peritumoral Resonance Imaging and Histological Classification edema (Figure-1).This finding is common in of Intracranial Meningiomas in 112 Dogs.J Vet meningioma.It is more frequently encountered with Intern Med 22(3): 586-595.masses located in the olfactory peduncles and frontal 3. Long S (2006) Neoplasia of the nervous system.In: (Ed.) VCH, editor.Braund's clinical neurology in lobes of the cerebrum [2].