Basophilic round bodies in gastric biopsies little known by pathologists: iatrogenic yttrium 90 microspheres deriving from selective internal radiation therapy.

Selective internal radiation therapy is a relatively new technique that irradiates primary and metastatic liver cancer using yttrium 90 microspheres. Increasing reports have shown this to be a useful treatment for unresectable primary hepatocellular carcinoma and others metastases from colon, lung, breast, sarcoma, and ocular melanoma. On the other hand, more and more therapy-related complications have been described. Since the morphologic description of injured organs are relatively uncommon, we report 2 cases of selective internal radiation therapy-related gastric injury, which represent basophilic round bodies in gastric biopsies little known by pathologists. The appearances in esophagogastroduodenoscopy include gastrointestinal ulcer, edema, and bleeding. Histological findings are mucosal atrophy, mild to moderate cytologic atypia, edema of the stroma, and inflammatory infiltration. The most characteristic feature is the presence of round blue and dark microspheres in the stromal blood vessels.