Case 011: 67 Year-Old Male with Epigastric Pain
Contributed by Soumya Pandey M.D and Andre Thompson, M.D., Supervised by Ehab Rabaa, M.D.
A 67 year old male with history of rectal carcinoma metastatic to the liver, status post-radiation therapy, now presenting with epigastric pain.
Endoscopic impression: Rule out radiation injury
A- Duodenal bulb: three fragments of soft tissue measuring 0.5 cm x 0.4 cm x 0.2 cm in aggregate; labeled with yellow ink and totally submitted.
B- Antrum: three fragments of soft tissue measuring 0.5 cm x 0.4 cm x 0.2 cm in aggregate; labeled with green ink and totally submitted.
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- Duodenal bulb and gastric antral mucosa with reactive changes, mild chronic inflammation, giant cell formation and multiple dark spheres, highly suggestive of Selective Internal Radiation Therapy (SIRT)-related injury.
- Silver stain is negative for H. pylori.
- Dysplasia/malignancy not identified.
Both biopsies in this case show multiple dark blue “crystalloid” pellets embedded in the lamina propria. Mild chronic inflammatory response and multiple scattered giant cells are seen in the background. These pellets are likely to be microspheres related to SIRT.
Selective internal radiation therapy (SIRT) is a recently FDA- approved, alternative therapeutic modality for the treatment of unresectable colorectal hepatic metastases. Biocompatible resin based yttrium 90 labeled microspheres are administered via the hepatic artery branches where they become lodged within the microvasculature of the tumor. The treatment is relatively selective since the hepatic tumors derive their blood supply almost exclusively from the hepatic artery whereas the normal liver parenchyma is largely supplied by the portal vein. The physical half-life of 90Y is about 2½ days and continual radiation emission lasts for ~14 days, destroying the tumor once the microspheres are lodged within the tumor microvasculature.
Encouraging results have been reported following previous studies of SIR spheres in metastatic colorectal cancer.
However it has the potential to cause adverse effects especially if the microspheres are incorrectly delivered to the arteries supplying the stomach, duodenum, pancreas and other organs. Gastric and/or duodenal ulceration, esophagitis, pancreatitis, hepatitis, and cholecystitis have been reported in various patients undergoing this therapy. The incidence of such adverse effects have been reported to range between 0 to 29% in previous studies. These adverse effects generally manifest within the first 2 months, but can manifest up to 5 months.
Microscopic features of acute and chronic radiation-induced gastroduodenitis range from apoptosis, epithelial flattening, and glandular cystic dilatation to nuclear atypia, capillary ectasia, and prominent endothelial cells.
Biopsies are more efficient than endoscopy in diagnosing SIRT- associated gastroduodenitis since microspheres can be easily identified under the microscope.
Hence pathologists should be aware if this complication and the characteristic appearance of the micro spheres to prevent them from being misinterpreted as primary tumors of stomach, duodenum or other involved organs.
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