58-year-old woman referred for abdominal discomfort. She was operated on for breast carcinoma in 1996. One year later, in a control ultrasound and abdominal CT scan, a multicystic pancreatic mass was discovered, with negative biopsy aspiration puncture for malignant cells. She was asymptomatic until 2000, when she began to experience dull abdominal pain. Physical examination and laboratory tests were rigorously normal. Blood tumour markers (CEA, Ca 125 and Ca 19.9) were negative. Abdominal ultrasound: multiple cystic formations throughout the pancreatic cell, multitabulated, with a solid component and some with microcalcifications, of varying size, the largest being 3 cm, and with no flow inside. All this was compatible with giant pancreatic cystadenoma. Abdominal CT and MRI with contrast confirmed these findings. Fine needle aspiration of one of the cysts was performed and no malignant cells were observed. Tumour markers in the cystic fluid showed Ca 125: 786 IU/ml (vn: 0-35), Ca 19.9: 174 IU/ml (vn: 0-37), and normal CEA. A diagnosis of giant cystadenoma of the pancreas, probably serous, was made. The patient has not presented any clinical or radiological changes since the first imaging study 6 years ago. After discussing this with the patient and with the Surgery Department, both refused surgical treatment for the moment.