LAUSR

A 79-year-old Caucasian man presented with 2 months of post-prandial right upper quadrant pain, nausea, and weight loss. On exam, he was anicteric, without jaundice, and his abdomen was soft, non-distended, and non-tender, without organomegaly. Admission labs were notable for alkaline phosphatase 502, AST 123, ALT 197, with total bilirubin 1.0, without leukocytosis. CEA, CA 19-9, and AFP were within normal limits. Ultrasound revealed a distended, heterogeneous gallbladder with gallstones and diffuse mural thickening (Fig. 1). Contrast-enhanced CTof the abdomen revealed a 7.1-cm heterogeneously enhancing soft tissue mass with extrahepatic biliary ductal dilatation (Fig. 2a). PET-MRI demonstrated FDG-avid locally confined disease, with extensive soft tissue thickening centered around the gallbladder involving liver segments 4B and 5 (Fig. 2b, c). During the operation, the patient underwent multiple biopsies which on frozen section were consistent with fibrosis. The mass and surrounding fibrosis were significant and distorted the normal anatomy. He underwent a radical cholecystectomy with en bloc extended right colectomy, as a portion of the transverse colon was adherent to the mass and could not be safely separated. During the operation, it was unclear whether this was a cancer or chronic cholecystitis with perforation of the gallbladder, with all frozen sections consistent with chronic fibrosis. Gross examination was notable for a 7.0-cm mass which was invasive into the liver and adherent to the colon (Fig. 3). Histopathological examination of the tumor revealed poorly differentiated small cell neuroendocrine carcinoma invading the adjacent hepatic parenchyma (Fig. 4a, b). The margins were all negative, and there was no evidence of malignancy in the portal lymph nodes. The tumor stage for this patient was IIIA, T3N0M0. On immunohistochemical study, the tumor was synaptophysin-positive, cytokeratin-positive, CD 56–positive, and PDL-1-negative (Fig. 4c-f).