Recurrent gastrointestinal bleeding after Peptide Receptor Radionuclide Therapy for a small intestine neuroendocrine tumor

We report a case of a patient who received three cycles of Peptide Receptor Radionuclide Therapy (PRRT) with [177Lu] Lu-DOTATATE for a small intestine neuroendocrine tumor (siNET) and developed recurrent GI (gastrointestinal) bleeding. These complications required four admissions on intensive care unit (ICU), transfusion of fourteen units of packed cells and finally surgery. Radiation safety precautions were respected at all hospital wards. Histopathology of the culprit lesion did not reveal tumor, but showed a large-caliber angiodysplastic lesion. The somatostatin receptor (SSTR) positive tumor consisted of a confluent mass of adenopathies invading the mesenteric vein. We hypothesize the amino-acid infusion, which is supportive therapy given prior to PRRT, caused vasodilatation in the pre-existing angiodysplastic lesion. The vasodilatation together with the high venous pressure due to tumoral invasion of the mesenteric vein may have aggravated bleeding symptoms.