Case Number : Case 2126 - 2 August 2018 Posted By: Raul Perret

Favour shwannoma

Myxopapillary ependimoma.

Agreed with both although I like myxopapillary ependymoma a little bit better.

This is case of ancient change in a schwannoma. Important clues to consider this entity are the hyalinized blood vessels, the presence of prominent cleft artifact and in some cases the focal nuclear atypia (usually without mitotic activity). It is also useful to check for a capsule (quite prominent in this particular example. In addition, this case had prominent pseudoglandular structures that can be a potential pitfall. S100 was diffusely positive and ki66 was low. In regards to the differential with myxopapillary ependymoma, although s100 can be positive and may rarely arise on the subcutis of the lumbar region, in this case there were't true papillae centered by hyalinized blood vessels nor rosettes. Thank you for the comments

Sorry, forgot to mention that sox10 was diffusely positive also in this case, a feature that also helps in the distinction between ependymoma/myxopapillary ependymoma and schwannoma

Raul, i always get excited when i see your posts. Really awesome cases and info. Lucky to have you here.