Venous Tumor Thrombus in Nonfunctional Pancreatic Neuroendocrine Tumors

OBJECTIVE. We sought to determine the incidence of venous tumor thrombus in nonfunctioning pancreatic neuroendocrine tumors. MATERIALS AND METHODS. We reviewed CT images of patients with a diagnosis of nonfunctional pancreatic neuroendocrine tumors over a 4-year period. For patients who underwent surgery, changes to surgical plans related to the tumor thrombus were also recorded. RESULTS. CT showed venous tumor thrombi in 29 of the 88 patients (33%; 95% CI, 23-44%). This CT finding was not accurately reported in 18 of the 29 patients (62%; 95% CI, 42-79%). Of the 39 patients who underwent surgery, venous tumor thrombi were detected in 11 patients (28%; 95% CI, 15-45%) and were confirmed by pathology. Microscopic venous tumor thrombi in 10 patients were not detected by CT. Pathologic results showed venous tumor thrombi in 21 of the 39 patients (54%; 95% CI, 37-70%) who underwent surgery. The surgical plan was significantly changed in two of the 11 patients with gross thrombi (18%; 95% CI, 2-52%) who underwent surgery. There was no change in the surgical plan for the 10 patients with microscopic tumor thrombi. CONCLUSION. The incidence of venous tumor thrombus detected by imaging was 33% in our study. This imaging finding was not accurately reported on the radiology report in 62% of the patients. In 18% of the patients with gross venous tumor thrombi, there was a significant alteration in the surgical plan. It is critical for the radiologist to be aware of the association of venous tumor thrombi in patients with nonfunctioning pancreatic neuroendocrine tumors and to report these findings.