A healthy 31-year-old female presented with a 1-year history of microcytic anemia, which was associated ith abdominal pain and a 10-pound weight loss. On physical xamination, there was a palpable tender mass in the left upper uadrant of the abdomen. Previous investigations with an sophagogastroduodenoscopy and capsule endoscopy were esentially normal. However, an ultrasound of the abdomen reealed a complex multiseptated cystic mass measuring 16.5 11.5 cm within the pancreatic tail, as well as splenomegaly. ubsequent computed tomography scan of the abdomen conrmed the presence of the multiseptated lesion and it appeared o be closely associated with both the stomach and the body nd tail of the pancreas. Figure A shows a CT coronal image of the dumbbell-shaped multiseptated pancreatic mass, and an axial image is shown in Figure B. Further imaging with endoscopic ultrasound (EUS) revealed a multiseptated, predominantly cystic extrinsic mass, which appeared to be originating from the distal pancreas and also invading the stomach. Its ultasonographic features were consistent with a cystadenoma (Figure C) and scant mucin was visible on EUS-guided fineneedle aspiration. Serum tumor markers including carcinoembryonic antigen, carbohydrate antigen (CA) 19-9 and CA 125 were all within normal limits. During surgical exploration, a 19.5-cm encapsulated multilocular cyst was completely resected via distal pancreatectomy and splenectomy with en bloc subtotal distal gastrectomy, as the lesion was inseparable from the stomach. A gross image of the pancreatic mucinous cystic neoplasm encased in a smooth outer wall is seen in Figure D, and Figure E shows the multilobulated nature of this lesion in a cross-sectional image. This mass was confirmed to be originating from the pancreatic tail, with invasion of the adjacent gastric wall possibly because of prior cyst rupture leading to local inflammation and adhesion. Furthermore, it was occluding the splenic vein, and hence causing extensive venous congestion with resultant splenomegaly. On histology, the pancreatic mucinous cystic neoplasm was composed of glands lined by tall, mucinproducing cells, and ovarian-type stroma was also present without any evidence of invasive carcinoma cells (Figure F; HE original magnification 100). Additionally, the ovarian-type stromal cells