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Nonductal tumors of the pancreas. The importance of laparotomy.

OBJECTIVES
To delineate the incidence of nonductal pancreatic neoplasms and determine whether distinguishing clinical or radiologic characteristics exist.


METHODS
From 1977 through 1990, we examined 353 patients with a pancreatic mass as demonstrated on abdominal computed tomography or ultrasonography. Patients with chronic pancreatitis or functioning neuroendocrine tumors were excluded. All patients underwent operative exploration for histopathologic diagnosis and resection when possible.


RESULTS
Adenocarcinoma of the pancreas was seen in 322 patients. The remaining 31 patients (8.8%) were found to have nonductal tumors of the pancreas, including nonfunctioning islet cell tumors (15), cystadenoma (nine), lymphoma (five), lipoma (one), and mesothelioma (one). These neoplasms were evenly distributed between the head and tail of the pancreas, while most of the ductal pancreatic carcinomas were located in the pancreatic head. While abdominal computed tomography and ultrasonography accurately identified most cystic neoplasms, the remaining nonductal lesions were indistinguishable from ductal pancreatic tumors. Preoperative biochemical studies and liver function tests failed to separate ductal and nonductal pancreatic masses. Average survival for patients with nonductal lesions was significantly longer compared with ductal tumors of the pancreas.


CONCLUSIONS
Because increasing reliance on advanced radiologic and invasive nonoperative diagnostic testing may deny proper surgical therapy to patients with nonductal neoplasms of the pancreas, laparotomy and histopathologic diagnosis are advisable in most patients with an isolated pancreatic mass.