Correlation of computed tomography imaging features and pathological features of 41 patients with pancreatic neuroendocrine tumors.

Abstract

BACKGROUND/AIMS Pancreatic neuroendocrine tumors (PNET) are relatively rare. Here, we present clinical and pathological characteristics of PNETs to show a relationship between computed tomography (CT) imaging and the 2010 World Health Organization (WHO) classification. METHODOLOGY We retrospectively reviewed the records of 41 PNET patients who were treated between 2002 and 2012. All tumors were classified as neuroendocrine tumor (NET) grade 1 (G1), NET grade 2 (G2), or neuroendocrine carcinoma (NEC) grade 3 (G3) on the basis of the 2010 WHO classification system. RESULTS Twenty-five tumors were classified as G1, 11 as G2, and five as G3. Mean sizes of the G1, G2 and G3 tumors were 1.84 ± 0.54, 4.90 ± 0.84, and 5.62 ± 1.18 cm, respectively, (P < 0.01). A PNET is typically hypervascular and exhibits contrast enhancement on enhanced CT. Higher percentage of G1 tumors demonstrated typical imaging and showed a significantly greater distinct mass compared with G2 and G3 tumors. CONCLUSIONS Although PNET has many imaging features that appear on CT, G2 and G3 tumors often show atypical imaging features, particularly with large sizes and/or ill-defined features, when compared with G1 tumors. If a PNET has atypical imaging features, possibility of malignancy should be considered.