Cystic duct cyst in adults: a systematic review of the sixth entity.

Over the past two decades, there have been an increasing number of reports describing a sixth type of choledochal cyst (cystic duct cyst) in adults that was not included in Todani's classification. This sixth entity has not yet been systematically reviewed in the literature. We therefore explored this condition in adults from the perspective of the clinical presentation, diagnosis and treatment through a systematic review of the evidence. The final analysis included 33 reported cases, with 55% of them reported in Asia. The mean age was 39.3 years old, with a female-to-male ratio of 1.5:1. Magnetic resonance cholangiopancreatography was accurate in establishing the diagnosis in 69% of cases. Where reported, standard laparoscopic/open cholecystectomy was performed in about 74% of patients, while around 25% of them needed extensive surgery. Associated malignancy was reported in 6.1% of cases, while 28% of patients had co-existent gallstone-related disease. No significant post-operative morbidity or mortality was reported. In this era of emergency laparoscopic cholecystectomy, surgeons should be aware of this rare condition, with the particular understanding that it is associated with gallstone-related disease in a significant number of reported cases.