A 69-year-old woman was admitted to a nearby clinic complaining of abdominal pain. Abdominal CT showed a 10 cm diameter huge cystic lesion in the body and tail of the pancreas. The patient was referred to our institution for treatment. Endoscopic ultrasonography (EUS) revealed a cystic mass with a solid lesion. Endoscopic retrograde pancreatography(ERP) demonstrated mucous at the opening of the papilla of Vater and dilatation of the pancreatic duct with a solid nodule. Contrast radiography revealed a fistula from the tumor to the jejunum. A biopsy specimen from the lesion showed adenocarcinoma. Intraoperative findings showed a tumor occupying the pancreas body and tail with suspected invasion to the stomach, jejunum, and transverse colon. We performed distal pancreatectomy with partial resection of stomach, jejunum, and colon. Pathological findings showed an invasive type of IPMC, with invasion to the subserosal layer of the stomach and colon and the mucous layer of the jejunum. While IPMC is recognized as a slow growing malignancy, some cases of invasive carcinoma with fistulation into adjacent organs have been reported. To our knowledge, a case of IPMC penetrating to 3 adjacent organs is rare.