Patient with unilateral hearing loss and a mass in the middle ear. Schwannoma is suspected. Biopsy is shown. Short thread follows...
The lesion is composed of cells arranged in solid sheets, often with a plasmacytoid appearance, also occasional glandular structures. Mitotic figures are hard to find. No necrosis.
Cells are strongly immunoreactive to chromogranin A. Also positive for synaptophysin and INSM1 (not shown). Could this be a paraganglioma?
So, an epithelial neuroendocrine tumor then! But wait, is this a metastasis from somewhere? Or could it be a primary lesion? Here is SATB2! 🧐
So, small intestinal NET metastatic to the middle ear! Or? No? Sounds off, right? Let's see... Here is pancreatic polypeptide (PP):
Well, it's NOT a metastatic pluri-hormonal "NET-kenstein monster" of the GI tract! This is a middle ear neuroendocrine tumor! ✅Well diff NET from L cells ✅CgA+, SYP+, INSM1+ ✅L cell profile ("hindgut") with SATB2+, PP+, gluc+ ✅Keratins+ (differ from PGL) ✅Rarely serotonin+