Papillary meningioma in the dog: A clinicopathological case series study

- Despite histological findings, an aggressive behavior can suspect for canine PM.
- This tumor shows a high rate of post-surgery recurrence and a low survival time.
- The biological malignancy of canine PM seems to be correlated to tumoral necrosis.
- As for DCX, E-cadherin, and N-cadherin we lack of conclusive results.

Papillary meningioma (PM) is one of the most aggressive variants of meningioma in humans and classified as grade III by WHO system. To date, the biological behavior of PM is still not clear in dogs. This study investigated the correlation between histopathological findings of 16 canine PMs and follow up data. Moreover, the expression of doublecortin, E-cadherin, and N-cadherin was investigated by immunohistochemistry. The supratentorial compartment resulted the most common involved. Despite the low grade of histological malignancy, 87.5% of dogs that underwent surgery experienced tumor recurrence. Intratumoral necrosis was observed in a strict correlation with malignancy histological parameter and tumor recurrence. The post-surgery mean survival time was much lower than thus observed in the most common histological subtypes. This data were also confirmed in dogs that received a conservative treatment alone. Tumors with a severe clinical behavior showed a high N-cadherin expression versus a low or absent E-cadherin expression.