We received an unusual case on our neuropathology service this week. The specimen was a 4 cm frontal, extra-axial mass that was dural-based, abutting the falx cerebri. MRI showed intense enhancement with surrounding vasogenic edema and a small dural tail. There was only mild mass effect and diffusion weighted imaging (DWI) showed no diffusion restriction. Cerebral arteriography showed a hypervascular lesion. Left middle meningeal artery embolization was performed preoperatively. At craniotomy the tumor was liquid and necrotic-appearing and the excised specimen was sent to us for pathological examination. The histological appearance is depicted below (click on photos to get higher resolution):
Glassy, eosinophilic cytoplasm with inclusions
Atypical cytology with some prominent nucleoli (occasional mitoses were also identified [~1-2 per 10 high-powered fields])
Focal areas of necrosis and hemorrhage
MIB-1 (Ki-67) immunostain showing a 15-20% proliferation rate.
Additionally, a vimentin immunostain showed strong diffuse cytoplasmic positivity and an EMA immunostain showed positive membrane staining. Cytokeratin immunostain was negative. How would you diagnose this case?
Glassy, eosinophilic cytoplasm with inclusions
Atypical cytology with some prominent nucleoli (occasional mitoses were also identified [~1-2 per 10 high-powered fields])
Focal areas of necrosis and hemorrhage
MIB-1 (Ki-67) immunostain showing a 15-20% proliferation rate.
Our diagnosis was:
ReplyDeleteRhabdoid meningioma (WHO grade III). The necrosis, mitoses, and proliferation rate helped to clinch our diagnosis. This is an aggressive variant of the usually benign, nonrecurrent meningioma category. This, along with the papillary and anaplastic/malignant meningiomas, make up the WHO grade III meningiomas.
Wow! Rara avis! Did you see any brain invasion? Sometimes I'll get a GFAP immunostain to highlight the brain being invaded by an atypical meningioma. Of course, in this case, brain invasion would be of purely academic importance since you're already in Grade III territory. Did you send the case out for a second opinion? Given the rarity of the diagnosis, I would be tempted to do that.
ReplyDeleteWe did not end up getting a GFAP on this case. I will order one for teaching purposes and follow-up on an additional post. Also, if this were my case, I would certainly send out for second opinion. I will bring that topic up with my attending, but I also have to respect his judgment on whether he wants to do it!
ReplyDeleteRhabdoid meningioma was the first thing I thought of when I saw the case, but I've never seen an actual case with this diagnosis. Let us know how the patient does in the coming months, if you think of it. Thanks for sharing this case!
ReplyDeleteHi Chris,
ReplyDeleteI tried to answer your question about neuropathology fellowships on my blog (http://neuropathologyblog.blogspot.com). Sorry it took so long to get back to you!
Brian
Nice discussion Chris. Thanks for the link
ReplyDeleteadam
Regarding Chris' question about Sen. Ted Kennedy's diagnosis: The New York Times reports that he has a "malignant glioma", and is not more specific than that. Statistically, the most likely diagnosis is glioblastoma, but we don't know for sure.
ReplyDelete-- Brian E. Moore, MD
This is a great case. Rare as hen's teeth.
ReplyDeleteChris, would you mind sending me an email via the contact form on pathtalk.org (http://www.pathtalk.org/contact). I have a "blogging proposal" for you, but I can't find your email address anywhere. Thanks,
Kenny Youens, MD