Computed Tomographic Features of Primary Small Cell Neuroendocrine Tumors of the Gallbladder

Purpose This study aimed to report the computed tomography (CT) imaging features of primary small cell neuroendocrine tumors of the gallbladder (PSCNETGs). Materials and Methods The CT examinations of 9 patients (5 women, 4 men; median age, 57 years) with histopathologically proven PSCNETG were reviewed. Computed tomographic images were analyzed with respect to morphologic features of primary tumors and accompanying lymph nodes. Results All PSCNETGs were visible on CT, with a median largest axial diameter of 60 mm (Q1, 30 mm; Q3 mm, 82; range, 25-86 mm). These tumors presented with extraluminal growth (8/9; 89%), heterogeneous enhancement (8/9; 89%), gallbladder replacement greater than 50% (5/9; 56%), hepatic metastases (5/9; 56%), and direct liver involvement by tumor (4/9; 44%). Enlarged lymph nodes were present in all patients (9/9; 100%) with a median largest axial diameter of 39 mm (Q1, 23 mm; Q3, 48 mm; range, 12-62 mm). Vessel encasement by lymph nodes was present in 6 (67%) of 9 patients. Conclusion Primary small cell neuroendocrine tumors of the gallbladder predominantly presents as a large, heterogeneous gallbladder mass with extraluminal growth in association with large metastatic lymph nodes and intrahepatic metastases.