True Carcinosarcoma of the Gallbladder: A Case Report and Brief Review of the Literature.

Introduction: Carcinosarcoma of the gallbladder (CSGB) is very rare, accounting for less than 1% of gallbladder malignancies. Therefore, the biological behavior is not well known. We report the case of a patient with CSGB who showed long-term survival after treatment with surgery and postoperative adjuvant chemotherapy.

Case Presentation: A 79-year-old man was referred to our department with suspected gallbladder cancer after undergoing positron emission tomography-computed tomography (PET-CT) scan for preoperative examination of lung cancer, which showed strong accumulation in the gallbladder. Abdominal contrast-enhanced computed tomography (CT) demonstrated a heterogeneous enhanced, 25-mm mass in the anterior wall of the gallbladder fundus. Cholecystectomy and hepatoduodenal mesenteric lymph node sampling revealed a polypoid tumor. Histopathological findings showed a mixture of adenocarcinoma and sarcoma with spindle-shaped cells. Immunohistochemical s taining of the s arcoma s howed negative results for the epithelial markers and positive results for the mesenchymal markers, leading to a diagnosis of true CSGB. We administered S-1 as postoperative adjuvant chemotherapy and was reported to be alive 45 months after surgery without recurrence.

Conclusion: CSGB has a poor prognosis, but if radical resection can be performed, there is a possibility of long-term survival. Further case studies and treatment options are needed to help understand this disease.