Can a lesion indicative of multiple sclerosis be mistaken as an arachnoid cyst?

[ashlyn0210]

I was told I have a 10mmx11mm arachnoid cyst located at the left velum interpositum. Cyst was found when looking for lesions to indicate multiple sclerosis. No lesions were found. I’ve supposedly had cyst all my life yet I’ve had multiple brain scans done throughout my life and a cyst was never mentioned. I was recently told by a nurse with MS that her lesions actually look like small cysts. Curious to know if maybe the cyst was a misdiagnosis and that it’s actually a lesion especially given it’s supposedly very rare location for an arachnoid cyst.

[supermum_ms]

Your welcome and i hope you get more information about it from your second opinion and hopefully some better pain relief options to explore too, Good luck.....JJ

[supermum_ms]

Hi and welcome,

I think an arachnoid cyst located in a rare location but still an identified cyst location, which the velum interpositum is, would be unlikely to be mistaken for an MS demyelinating lesion of the same size, more so when you don't have any demyelinating lesions at all in other locations....

"Arachnoid cysts are similar to CSF in signal intensity in most cases unless they are complicated with hemorrhage. Diffusion-weighted MR imaging reveals that they have no water restriction, and helps to distinguish them from epidermoid cysts which show water restriction."
https://posterng.netkey.at/esr/viewing/index.php?module=viewing_poster&task=viewsection&pi=3893&ti=19399&searchkey=

Arachnoid cysts are predominantly found in children but they can be either congenital or acquired, when acquired it's usually following bouts of inflammation, subarachnoid chemical irritation, trauma, or hemorrhage, from my understanding when they are discovered in adults it's more commonly an incidental finding and thought to be more likely congenital.

If your saying this has never been noted prior on any other MRI's so it can't be or unlikely congenital, the only things that i can come up with that's a possible explanation is it was just visible but smaller on the prior MRI's and missed before or that it is acquired and developed since your last MRI...i think the only way you'll know one way or the other is if you ask your neuro to review your prior scans and compare the results to check if you've always had it or if it is acquired.

I hope it helps......JJ

[ashlyn0210]

Thank you so much. It helps. I’m actually going for a 2nd opinion but more so I am just irritated it took years to tell me the size and location. Every time I would ask he would tell me it’s small and. It causing issues and that I’ve probably had it all my life. Yet I’m now dealing with the same headache for 3 weeks now along with pain off and on in left side of my neck and my neuro won’t do anything about it or look into it more. Pain management doctor at least gave me a toradol injection to try to help with the headache until I can get in to new neuro. Hydrocodone I’m on for fibromyalgia doesn’t even touch the pain of headache. Thank you for answering and also confirming where cyst is is a rare location. I have been having a hard time finding info about an arachnoid cyst in the velum interpositum besides finding that it’s rare. Seems like some things I get diagnosed with is rare and starting to feel lost. My family doesn’t seem to get it but at least my husband does. Thanks again.