Non-tumor forming and diffusely spreading invasive pancreatic cancer.

A 78-year-old man presented to our hospital with loss of appetite and epigastric discomfort. Computed tomography (CT) revealed dilation of the main pancreatic duct and three cystic lesions in the pancreatic neck, body, and tail. Endoscopic ultrasonography showed a mural nodule > 5 mm enhanced with Sonazoid in a cyst. Therefore, the patient was diagnosed with intra-ductal papillary mucinous neoplasm (IPMN) and underwent distal pancreatectomy. Macroscopic examination of the cut surface of the resected specimen showed no solid tumors in the pancreatic parenchyma. The histopathological diagnosis of the cysts was IPMN with low-grade dysplasia. Ten months after surgery, the serum carbohydrate antigen 19-9 level was elevated, and CT showed multiple peritoneal and pulmonary nodules, suggesting peritoneal dissemination and lung metastases. Since recurrence of pancreatic cancer was suspected, repeat histopathological examination of the resected specimen was performed, revealing small clusters of atypical epithelial cells diffusely spreading in the pancreatic tissue. The diagnosis was changed to invasive ductal carcinoma (pT2N1bM0, stage IIB). Invasive pancreatic cancer that does not form a solid mass, and shows diffuse spreading with small clusters is extremely rare. Imaging diagnosis and histopathological examination should be carefully performed in such cases.

Mucosal prolapse syndrome-like inflammatory polyp protruding from the appendiceal orifice masquerading as an appendiceal neoplasm: A rare case report.

We describe a case of a mucosal prolapse syndrome (MPS)-like inflammatory polyp protruding from the appendiceal orifice, mimicking an appendiceal neoplasm. A 48-year-old man presented with lower abdominal pain and elevated white blood cell count and C-reactive protein level. Computed tomography showed a swollen appendix with multiple small saccular lesions and periappendiceal fat stranding and small saccular lesions in the ascending colon and cecum. Ultrasonography showed a swollen appendix 25 mm in diameter with multiple saccular structures and a periappendiceal high-echoic area, suggesting appendiceal diverticulitis. Colonoscopy revealed an erythematous lesion protruding from the appendiceal orifice. An ileocecal resection was performed based on a preoperative diagnosis of appendiceal diverticulitis and tumor. Histopathological examination of the appendix showed multiple mucosal herniations with infiltration of inflammatory cells, indicating appendiceal diverticulitis. The tumor was characterized by glandular duct hyperplasia and stromal expansion with smooth muscle hyperplasia and was diagnosed as an inflammatory polyp resembling an MPS lesion. Although several studies have shown the macroscopic and endoscopic appearance of MPS-like inflammatory lesions associated with colonic diverticular disease, this case was the first to present an inflammatory polyp associated with appendiceal diverticulitis in which the lesion protruding from the appendiceal orifice was masquerading as an appendiceal neoplasm.