Multiple Meningiomas in a Cat

An 11 year-old DSH cat with a one-week history of circling, falling over and dragging the back legs was referred for imaging. 

MR images obtained (see below - bottom panel) show two well-defined broad-based extra-axial space-occupying lesions, almost symmetric, located at the level of right and left fronto-temporal-parietal region. Both show similar shape (oval), the left slightly bigger than the right. Both lesions show the same signal intensity pattern: they are mildly heterogeneous, predominantly and mildly hyperintense to white matter in T2W and FLAIR, mildly isointense in T1W and with moderate and generalised contrast enhancement. From the post-contrast images, short dural tail signs are seen bilaterally on the rostral and caudal aspects of the lesions, representing attachment to the meninges. 

The images on the top are from a human with multiple meningiomas - note the similarities.

Multiple meningiomas are rare in dogs, but slightly more common in cats. There are multiple theories regarding the pathogenesis of multiple meningiomas. One is the non-clonal theory, in which wide neoplastic fields in the dura mater give rise to multiple synchronous or metachronous meningiomas. Other theories suggest that multiple meningiomas are due to dissemination of tumour cells either by subarachnoid spread via the CSF or by surgical manipulation. In people, they can be a consequence of NF2 germline mutational inherent pattern, or as sporadic non-hereditary cases.

In the cats reported with multiple meningiomas, the same tumoral type was found in all lesions. 

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