70ish y/o male, gastric lesion, excision. Tumor is locaded in the submucosa, with infiltrative growth to the subserosal layer. Cells are arranged in solid sheets. Monomorphic appearance. Let's have a closer look! Follow the thread... 🧵
Cells with cytoplasmic clearing are noted, with focal hyaline-like stromal reaction. There is no necrosis, but occasional mitotic figures are seen.
Diffuse synaptophysin immunoreactivity... Could this be a gastic NET? Well, the tumor is keratin-negative (not shown), so perhaps a paraganglioma?
So, a keratin-negative gastric tumor with synaptophysin expression. Tumor shows cytoplasmic clearing and hyalinization of the stroma... Here is the smooth muscle actin stain:
This is a glomus tumor of the stomach! ✅Rare, mesenchymal tumor derived from smooth muscle. ✅Usually clinically benign (but not always!) ✅Look for cytoplasmic clearing, hyaline stroma. ✅Usually positive for synaptophysin. ✅May mimic NET, paraganglioma and epitheloid GIST!