Extracranial expansion of a feline meningioma

Abstract

Meningioma is the most frequently observed primary brain tumour in cats. Usually, it is associated with an intracranial expansion with consequent brain compression, oedema and brain herniation. Typical features of feline intracranial meningiomas are hyperostosis of the adjacent bone and intratumoral mineralisation. We describe a 13-year-old male neutered cat with a 1-year history of behavioural change. At clinical and neurological examination the cat showed signs consistent with right-sided forebrain lesion. Magnetic resonance images showed a right-sided extra-axial contrast enhancing mass in the region of the frontotemporal lobe. The overlying bone of the calvarium showed a marked defect with extracranial expansion of the tissue. Surgery was performed and the tumour could be exposed by a right-sided temporal approach. After extension of the bony defect the mass could be removed properly. The cat recovered well from surgery and a 12-month follow-up showed no persistent neurological deficits. Histopathological assessment of the tumour revealed a transitional grade 1 meningioma. Despite osteolysis and extracranial expansion of the tumour differentials should include menigioma in feline intracranial neoplasms.

Diagnostic Immunohistochemistry of Canine and Feline Intracalvarial Tumors in the Age of Brain Biopsies

“…108 A recently reported meningioma penetrated through the calvarium of a cat without surgical intervention. 56 Local implants of several intra-axial tumors may also produce metastases along ventricles or the subarachnoid space.…”

“…134 Meningiomas metastasize outside the cranium very rarely, but extracranial metastases or extensions through the calvarium are possible, especially of anaplastic tumors. 56,67,108,113 Vimentin is the classical immunohistochemical marker for detecting all subtypes of meningiomas, even anaplastic tumors, and most cases express S100 (Fig. 7).…”

Feline meningioma with extensive nasal involvement

“…Invasion by tumour cells, production of proteolytic enzymes, focal necrosis of the bone by pressure atrophy and ischaemia are considered to be possible mechanisms for this change. 3…”

Magnetic resonance imaging and computed tomographic characteristics of a glioma causing calvarial erosion in a dog

“…1,2 On the other hand, osteolytic skull changes associated with meningiomas are uncommon and have only been reported in two dogs and rarely in cats. [3][4][5][6] In human medicine, reactive osteolytic bone changes are more commonly described associated with meningiomas, sarcomas, and metastases, but there are a few reports of calvarial erosion associated with gliomas. [7][8][9][10][11] The pathophysiology of glioma-associated skull osteolysis is unknown.…”

“…Skull hyperostosis is detected in 23% and 73% of meningiomas in dogs and cats, respectively . On the other hand, osteolytic skull changes associated with meningiomas are uncommon and have only been reported in two dogs and rarely in cats . In human medicine, reactive osteolytic bone changes are more commonly described associated with meningiomas, sarcomas, and metastases, but there are a few reports of calvarial erosion associated with gliomas …”