A 52-year-old man, with no past history of interest, was studied after an abdominal ultrasound scan for a urological study revealed an intrahepatic cystic tumour which at first appeared to be an uncomplicated complex hepatic cyst. An abdominal CT scan was requested in which a cystic image of about 5 centimetres (cm) in diameter was found located between segments V and VIII in the shape of a bunch of grapes, with septa in its interior, some of which were thick and attracted significant contrast in some areas. Tumour markers were negative.
Given the asymptomatic nature of the picture, it was decided to follow up. In the radiological control carried out one year later, the lesion increased in size (9 x 7 x 7 x 7 cm) and was located in the porto-biliary confluence, without compressing it. Given the growth of the lesion, it was decided to operate on the patient given the possibility of malignancy of the lesion.

During surgery, a cystic, polylobulated tumour was observed at the junction of segments IV and V, bulging towards the hilum. The intraoperative biopsy was reported as a mucinous tumour without being able to rule out malignancy.
Given the possibility of a cystadenocarcinoma, a radical excision of the specimen was decided, and complete resection could not be performed. Dissection revealed fistulisation of the tumour to the right hepatic duct, outflow of mucinous content and intracystic polypoid lesions.
The definitive histological diagnosis was mucosecretory cystadenocarcinoma which, as it occurred in a male patient, was more aggressive.
The evolution has been favourable, with adjuvant chemotherapy with 5-fluorouracil and no recurrence at one year follow-up.