[A Case of Lymphoepithelial Cyst of the Pancreas for Which Malignancy Could Not Be Ruled Out Difficult Preoperative Diagnosis].

Lymphoepithelial cyst(LEC)of the pancreas is a relatively rare benign cystic disease of the pancreas. In this report, we describe a case of LEC in which a malignant tumor could not be ruled out by preoperative diagnosis and surgery was performed. The patient was a 72-year-old man. A simple CT scan of the chest and abdomen performed as a follow-up for another disease incidentally revealed a mass in the pancreatic tail. Enhanced CT of the abdomen showed a tumor approximately 3 cm in size at the pancreatic tail with no contrast effect. MRCP showed moderate signal on T2WI, high signal on T1WI, and high signal on T2WI on some cysts inside the pancreas. PET-CT showed slight uptake of FDG. Both tumor markers CEA and CA19-9 were normal. Therefore, malignant disease such as pancreatic IPMC could not be ruled out, and laparoscopic distal pancreatectomy plus splenectomy was performed. The pathology results showed a diagnosis of pancreatic lymphoepithelial cyst with slight differentiation into sebaceous gland.

[A Case of Pathologic Complete Response Achieved with Preoperative Pembrolizumab Therapy for Transverse Colon Cancer].

A 77-year-old female patient presented with a medical history of 4 cancerous lesions, each with a surgical history. She was referred to our hospital due to anemia. Upon examination, she was diagnosed with transverse colon cancer. Duodenal invasion was suspected, which made performing R0 surgery difficult; therefore, the NAC approach was chosen. Three courses of CAPOX were administered, resulting in tumor obstruction, leading to the formation of an ileum stoma. MSI testing revealed MSI-H, and pembrolizumab treatment was initiated. CT scans showed tumor shrinkage, and PET scans indicated no accumulation, resulting in a cCR. Colon resection including the lesion suspected of stenosis was performed with a strong desire for stoma closure and the determination of potential curative resection. Additionally, a partial resection of the duodenum was performed. Pathological examination did not reveal any evident tumor cells, leading to the determination for a pCR. The patient has been under postoperative surveillance for 1 year without any recurrence.