A case of poorly differentiated mucinous carcinoma of the gallbladder that exhibited a peculiar morphology.

A 65-year-old female presented with an elevated lesion that was identified in the gallbladder fundus via abdominal ultrasound during a medical checkup. The tumor was a pedunculated lesion, measuring 30mm in diameter, that exhibited a blood flow pattern with gradual dense staining throughout the equilibrium phase on the abdominal contrast computed tomography and a high signal intensity on T2-weighted magnetic resonance imaging. Histopathological findings revealed the proliferation of poorly differentiated adenocarcinoma, including signet ring cells, throughout the tumor along with the formation of a mucous lake. The patient was consequently diagnosed with poorly differentiated mucinous carcinoma of the gallbladder.

[A case of pancreatic neuroendocrine tumor presenting with main pancreatic duct invasion].

A 52-year-old male visited a local clinic with a subjective complaint of pain in the left side of his abdomen. Abdominal CT revealed the presence of a pancreatic body tumor. On EUS, the tumor presented hypoechoic signals with an obscure boundary, which continued from the pancreatic parenchyma to the inside of the main pancreatic duct. Abdominal contrast CT revealed a hypervascular tumor with densely stained pancreatic parenchyma. ERP findings revealed that main pancreatic duct invasion was suspected based on partial radiolucency in the duct. Distal pancreatectomy was performed, and a definitive diagnosis of pancreatic neuroendocrine tumor (WHO class G1) was made histopathologically.

[A case of dermoid cyst of the pancreas].

A 58-year-old man visited a local clinic after experiencing epigastric and dorsal pain. A computed tomography scan revealed a hypovascular mass in the pancreatic tail. T1-weighted magnetic resonance imaging (MRI) of the tumor showed a heterogeneous isointense signal and T2-weighted MRI showed a hyperintense signal. Contrast studies revealed contrast enhancement, showing a cystic wall and parts of a septal structure and lumen. Endoscopic ultrasonography revealed a multilocular hypoechoic tumor containing large quantity of debris. We experienced difficulty arriving at a diagnosis and are reporting this case of a pancreatic dermoid cyst, which was diagnosed based on pathological findings.

Acute pancreatitis caused by an ectopic mediastinal parathyroid adenoma.

A 22-year-old man was admitted to our hospital because of epigastric pain. Blood tests showed leukocytosis (8940 cells/mm(3)) and increased serum amylase levels (787 IU/L); an abdominal computed tomography (CT) scan revealed an enlarged pancreas and peripancreatic fluid collection. On the basis of these findings, he was diagnosed with acute pancreatitis. Hypercalcemia (13.5 mg/dL) and increased levels of parathormone (>3200 pg/dL) were also detected using a high-sensitivity assay; we therefore considered hypercalcemia and primary hyperparathyroidism to be the possible causes of the acute pancreatitis. A (99m)Tc-sestamibi scan showed accumulation of parathyroid tissue in the left mediastinum, and a tumor was noted on the left side of the aortic arch on a thoracic CT scan. Our final diagnosis was acute pancreatitis due to hypercalcemia induced by an ectopic mediastinal parathyroid adenoma. Ectopic parathyroid tumors can thus cause acute pancreatitis, and (99m)Tc-sestamibi and CT scans are useful for their diagnosis and localization.

Intraductal tubulopapillary neoplasm of the pancreas with somatic BRAF mutation.

Intraductal tubulopapillary neoplasm (ITPN) is a rare pancreatic tumor belonging to a newly recognized entity that is coined in the 2010 WHO classification. We present a case of ITPN-associated microinvasive adenocarcinoma that developed in an asymptomatic 78-year-old patient. The tumor demonstrated all the clinical, radiological, and pathological characteristics of ITPN, but it differs from other reported cases of ITPN in molecular analysis, which revealed a somatic mutation in BRAF (c.1799T>A; p.V600E) but no mutation in PIK3CA. Post-operative recurrence was discovered 34 months after tumor resection with negative margins and a 6-month course of adjuvant chemotherapy. To the best of our knowledge, this is the first case of ITPN with BRAF mutation. This case suggests that an activation of RAS-mitogen-activated protein kinase signaling pathway may play a role in development of some of ITPNs. A possible mechanism of tumor recurrence in ITPN is also discussed. Further case series with molecular study are awaited to delineate the clinicopathological and molecular characteristics of ITPN.