Primary Small Cell Neuroendocrine Carcinoma of the Gallbladder with Lymph Node Metastasis

Abstract

A 56-year-old woman who presented with right lower abdominal pain and discomfort that had lasted over 1 month was admitted to our hospital. Her past medical history includes cholelithiasis found 3 years ago without any treatment and virus B hepatitis diagnosed in other hospital a week before. Physical examination showed that a hard mass measuring about 4.0 cm × 3.0 cm was touched under the right costal margin. Tumor markers including antigen 19-9 (CA19-9) (18.5 U/ml), carcinoembryonic antigen (CEA) (1.53 ng/ml), cancer antigen 125 (CA-125) (6.42 U/ml), and alpha fetoprotein (AFP) (2.63 ng/ml) were all negative. Preoperative level of immunoglobulin G4 (IgG4) was also within the reference range. And serum hepatitis B surface antigen (HBsAg), hepatitis B e antibody (HBeAb), and hepatitis B core antibody (HBcAb) were positive. Abdominal unenhanced and contrast-enhanced computed tomography (CT) scan showed a heterogeneous enhancing soft tissue mass measuring 3.9 cm × 2.5 cm in the fundus of gallbladder and a 3.7 cm × 3.0 cm soft tissue nodule suspected of lymph node metastasis in the hepatic hilar. Cholelithiasis was also present (Fig. 1). The ultrasonic contrast also verified a 3.7 cm × 2.4 cm solid mass highly enhanced in the arterial phase and lower enhanced in the venous phase at the fundus of gallbladder. Both the CT and ultrasound considered a high possibility of gallbladder carcinoma with lymph node metastasis in the hepatic hilar. Eventually, the patient underwent a laparoscopic radical resection of gallbladder carcinoma including cholecystectomy and partial hepatic resection. The resected gallbladder was measured about 10.0 cm × 8.0 cm × 6.0 cm, with a solid mass in the fundus and a stone about 1.5 cm in diameter in it. Postoperative pathological examination confirmed a malignant tumor. Further immunohistochemical staining showed that the tumor was positive for PCK, CD56, Syn, and CgA negative for CK7 and CD45, with Ki67 index of 90% (Fig. 2). Taken together, these histological findings supported the diagnosis of small cell carcinoma of the gallbladder. No other primary sites have been identified. The postoperative recovery of the patient was good, and the patient was discharged on the 9th day after the surgery. The patient remains alive and is being followed up at our hospital every 3 months after surgery. Small cell neuroendocrine carcinoma (SCNECs) is a poorly differentiated type of neuroendocrine neoplasms (NENs) 1 . While the SCNECs is one of the most common pathological patterns of lung cancer, the occurrence of SCNECs in the biliary system is extremely rare. There are a limited number of publications regarding SCNECs of gallbladder, mostly comprising individual case reports or small retrospective series. Currently, the characteristics of SCNECs of gallbladder, including its clinical pathology and treatment, are essentially extrapolated from small cell lung cancer 2 . The etiology and pathogenesis of gallbladder SCNECs are not completely clear. Since neuroendocrine cells are not present in the native gallbladder, it is thought that intestinal metaplasia as a result of * Fu-Yu Li [email protected]