Non-neoplastic pancreatic lesions that may mimic malignancy

The widespread use of abdominal ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) has resulted in an increased identification of asymptomatic pancreatic lesions. Preoperative diagnoses of pancreatic lesions can be difficult. Solid and cystic lesions and anatomic variants of normal can all mimic tumor clinically and radiologically. Newer imaging modalities have increased the likelihood of the accurate diagnosis of non-neoplastic pancreatic disease, however, despite the many advances; it still remains a challenge to differentiate rarer non-neoplastic entities and inflammatory masses from adenocarcinoma, preoperatively. Adding to the challenge is the fact that a variety of inflammatory, solid and cystic non-neoplastic lesions have significant clinical and radiological overlap with malignancies. About 5-10% of pancreatectomies performed with the primary clinical diagnosis of pancreatic carcinoma are later proved to be essentially non-neoplastic lesions. It is vital to include these non-neoplastic entities in the differential diagnosis while working up abnormal clinical and radiological pancreatic findings because it may drastically alter therapeutic options for the patients. The significance of recognizing these lesions preoperatively is to help to guide the clinical decision-making process and the avoidance of an unnecessary pancreatectomy. Examples of such entities include chronic pancreatitis, sarcoidosis, intrapancreatic accessory spleen (IPAS), lymphoid hyperplasia, lipomatous pseudohypertrophy (LPH), lymphangioma, lymphoepithelial cyst (LEC) and endometriosis.