To investigate the single-center experience in the surgical diagnosis and treatment of malignant transformation of choledochal cysts in adults.

The clinical data of 77 adult patients with choledochal cysts admitted to the First Affiliated Hospital of Guangxi Medical University from January 2013 to June 2025 were retrospectively analyzed. As a retrospective study, the requirement for informed consent was waived, and the study complied with medical ethical requirements. There were 21 males and 56 females, aged 18-76 years, with a median age of 37 years. Cases of malignant transformation of choledochal cysts were identified, and the relevant clinical data were analyzed. Survival analysis was performed using the Kaplan-Meier method and log-rank test.

Malignant transformation occurred in 10 of the 77 patients with choledochal cysts, with an incidence of 13% (10/77). Among them, there were 3 males and 7 females, aged 26-72 years, with a median age of 40 years. Seven patients underwent radical pancreatoduodenectomy (radical surgery group). The operative time ranged from 398 to 593 min, with a median of 510 min; intraoperative blood loss ranged from 300 to 1,400 ml, with a median of 800 ml. Two patients developed postoperative complications of Clavien-Dindo grade Ⅲa or higher, and no deaths occurred within 90 d after surgery. Three patients underwent palliative surgery (palliative treatment group), including liver metastasis biopsy, biliary stent implantation, and choledochal cyst resection combined with palliative internal biliary-enteric drainage in one case each. Follow-up ended on June 30, 2025. The follow-up duration of the 7 patients after radical surgery ranged from 1 to 146 months, with a median survival time of 16 months. During follow-up, two patients died at 12 and 18 months after surgery, respectively. The 1-, 2-, and 3-year survival rates were 83.3%, 62.5%, and 62.5%, respectively. The follow-up duration after palliative surgery ranged from 1 to 6 months, with a median survival time of 5 months. During follow-up, all 3 patients died at 1, 5, and 6 months after surgery, respectively; the 1-, 2-, and 3-year survival rates were all 0. Kaplan-Meier survival analysis showed that the median survival time in the radical surgery group was significantly longer than that in the palliative treatment group ( χ² = 8.64, P = 0.003), indicating a more pronounced survival benefit.

The primary preventive strategy for malignant transformation of choledochal cysts in adults is early diagnosis and complete excision of the choledochal cyst. Particular emphasis should be placed on complete management of the pancreaticobiliary junction and maximal removal of the intrapancreatic cyst wall to reduce residual choledochal cyst tissue. Lifelong regular follow-up is required after choledochal cyst excision. Once malignant transformation of a choledochal cyst is diagnosed, pancreatoduodenectomy should be attempted whenever feasible.