A 45 years old female presented with vague abdominal pain. On laboratory investigation, amylase was normal but CEA was raised. CT scan was performed, showing a hypodense lesion in pancreas, which had internal septation and wall calcification. Most probable diagnosis is:
Serous cystadenoma Mucinous cystadenoma Intraductal mucinous papillary neoplasm Acinic cell tumour