Presentation of case
A 43-year-old male patient was found to have a pancreatic tail cyst upon abdominal ultrasonography on physical examination. He had no subjective symptoms, or medical history. Laboratory data, such as complete blood cell count, hepatic and renal functions, as well as serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) were within conventional limits. In addition, amylase, lipase, and blood glucose levels were normal. On further referral to the study hospital, computed tomography (CT) revealed a cyst with a diameter of 15 mm in the pancreatic tail. The cystic lesion was monocystic and had an intensity-enhanced area around the cyst in the low intensity area (Fig. 1). Magnetic resonance imaging (MRI) revealed a lesion with depleted and enhanced intensities on the T1 and T2-weighted figures, respectively. Diffusion-weighted MRI displayed increased signal potency in the peripheral portion of the cystic lesion (the wall and the septa); the cystic contents presented reduced intensity on an enhanced MRI (Fig. 2).
Endoscopic ultrasonography (EUS) revealed a cyst with high-echoic lesions, a pancreatic tail, and calcification on the cyst margin (Fig. 3a). Endoscopic retrograde cholangiopancreatography (ERCP) displayed a slight displacement of the pressure superior to the duct, with no narrowing or disruption (Fig. 3b).
The findings of suspected cyst degeneration on CT and MRI with low intensity on T1-weighted figures and high intensity on T2-weighted figures were consistent with the characteristics of pNET. The preoperative diagnosis was pNET. According to the guidelines mentioned above, the first-line of treatment for pNET is surgery. A distal pancreatectomy was performed with concomitant splenectomy. The postoperative course was uneventful. The excised surface of the resected specimen revealed a multilocular cyst with solid nodules (Fig. 4a). Histopathological findings revealed the spleen, as well as, the red and white pulp in the parenchyma of the pancreatic tail. Since spleen tissue was found in the pancreatic tissue, we diagnosed it as an intrapancreatic accessory spleen cyst. The major and minor multilocular cysts had a maximum diameter of 17 mm; the luminal epithelium consisted of mature squamous epithelium with display of the subepithelial lymphoid tissue. The cyst lumen revealed keratin and cholesterol deposits in the clefts. The fact that lymphatic tissue occupies the majority of the cyst is a major feature of LECs and meets the diagnostic criteria for LECs. Ultimately, the patient was diagnosed with a LEC of the pancreatic accessory spleen.