Because of high suspicion of malignancy we
Because of high suspicion of malignancy, we chose endoscopic ultrasound (EUS) instead of MRI of the pancreas to detect the organic lesion that caused the distal CBD stricture because initial abdominal CT did not show any suspicious lesion in the pancreas. In addition, tissue sample could be obtained using EUS fine needle aspiration if any suspicious lesions are found. EUS revealed pancreatic duct dilatation in the head portion and one heterogeneous hypoechoic tumor of about 2.68 × 2.34 cm located at the uncinate process (Fig. 3). Fine needle aspiration from the uncinate process tumor was performed. The final harmine report showed negative results for malignancy.
MRI was performed to view the irregular enhanced lesion at the uncinate process of the pancreas on the arterial phase. Diffusion weighted images also showed relatively high signal intensity in the uncinate process (Fig. 4). A high malignancy potential of the pancreatic uncinate process was suspected from the imaging results.
We performed a Whipple operation with findings of a hard pancreatic tumor, which compressed to the distal CBD with dilatation. On gross appearance, it was a circumferential sclerotic tumor, measuring 2.5 × 2.5 × 1.5 cm in size, involving the pancreatic head. The margins of the peripancreatic tissue were free of tumor. Microscopically, vascular invasion was absent. Two out of 21 lymph nodes showed metastatic adenocarcinoma. It was proven to be a moderately to poorly differentiated pancreatic head adenocarcinoma (Fig. 5). According to the American Joint Committee on Cancer 7th Edition Staging, the pathologic TNM stage was T2N1M0, Stage IIB. After surgical intervention, the patient received systemic chemotherapy with gemcitabine.
Discussion Pancreatic cancer is the eighth leading cause of cancer-related deaths in Taiwan. The most common initial clinical presentation of pancreatic exocrine tumors is pain, jaundice, and weight loss. The initial clinical presentation depends on the location of the pancreatic tumor. Jaundice, steatorrhea, and weight loss are more common symptoms in patients with pancreatic head tumors compared with in those with tumors in the body or tail. Around 60 to 70 percent of exocrine pancreatic cancers are located in the head portion of the pancreas, while only 20 to 25 percent are found in the body or tail. Pancreatic head tumors with an initial presentation of painless jaundice tend to have a more favorable prognosis, making surgical intervention desirable. The present patient had a medical history of diabetes mellitus diagnosed less than 2 years ago. New onset diabetes mellitus can be an early sign of pancreatic head adenocarcinoma. Transabdominal ultrasonography is the first-line imaging study used in patients with suspected biliary obstruction of unknown etiology. Transabdominal ultrasonography is readily available, inexpensive, and does not use ionizing radiation. However, it is not a suitable screening tool for detection of pancreatic masses due to its relatively low sensitivity. A pancreatic carcinoma typically appears as a focal hypoechoic hypovascular solid mass with irregular margins. In one study, the sensitivity for detection of pancreatic masses has been reported to range from 67 to 90% because of high operator dependence. Multi-detector computed tomography (MDCT) is widely available and is the best-validated imaging modality for the evaluation of a patient with a suspected pancreatic mass. The typical image of pancreatic adenocarcinoma on MDCT is an ill-defined hypoenhancing mass. The sensitivity of MDCT for the detection of pancreatic adenocarcinoma is as high as 89–97%. However, the shortcoming of MDCT is its low sensitivity for small lesions (less than 1.5 cm) of pancreatic tumors. The detection rate of small lesions in pancreatic head by MDCT is only 67% in this study. In another study, the sensitivity was 100% for tumors >2 cm, but only 77% for tumors ≤2 cm in size. In the present case, the initial abdominal CT did not reveal the primary tumor in the pancreatic head, perhaps because of its size.