Chapter 72: Cystic Neoplasms of the Pancreas

INTRODUCTION

The collective phrase “cystic lesions of the pancreas,” typically described on cross-sectional imaging of the abdomen, refers to any cystic neoplasms of the pancreas and/or other cystic lesions, many of which cause “cyst-like” dilatations of the main or side branch pancreatic ducts. Specifically, the descriptor “cystic neoplasms of the pancreas” encompasses a wide variety of pathologic entities of the pancreas with variable malignant potential. The incidence of these cystic neoplasms seems to increase with age, with one autopsy study demonstrating that up to a quarter of elderly individuals harbor cystic lesions of the pancreas at their demise.¹ As the use of abdominal computed tomography (CT) and magnetic resonance imaging (MRI) is increasing, cystic lesions of the pancreas are being defined more frequently, with the majority asymptomatic at discovery.^2,3 Laffan and colleagues in 2008 estimated the incidence of asymptomatic discovered cysts on abdominal imaging for unrelated diagnoses at 2.6%.⁴ Some of these lesions will be malignant or have malignant potential at diagnosis, while others are clearly benign and may not warrant further surveillance. Resection of benign cystic pancreas lesions or those containing only high-grade dysplasia (premalignant) leads to nearly universal survival, while surgery for invasive carcinoma associated with cystic neoplasms generally has a more favorable prognosis than the results for resection of typical pancreatic ductal adenocarcinoma.^5-7 Thus, careful consideration must be given to the diagnosis and prognostic implications of these lesions. As more becomes known about these neoplasms, the treatment and observation algorithm will continue to evolve to minimize unnecessary interventions, while maximizing the impact of surgical treatment.

An ideal diagnostic approach would allow for the resection of only those lesions with concurrent or near-future risk of malignancy, while excluding from surgery those individuals with either nonenlarging benign lesions or a prohibitive operative risk, thus minimizing the potential occurrence of mortality and morbidity associated with the surgical treatment of these cystic lesions. Recent advancements in imaging by CT, MRI, and endoscopic ultrasonography (EUS), linked with refinements in the pathological, molecular, and genetic understanding of cystic neoplasms of the pancreas, have furthered this effort. History and clinical criteria, such as age, gender, presence of symptoms, location of the neoplasm within the pancreas, as well as morphology by cross-sectional imaging and cyst fluid analysis by EUS with fine-needle aspiration (EUS-FNA), all may play a role in the diagnosis of pancreatic cystic neoplasms and assessment of the need for resection. While the phrase “cystic neoplasm of the pancreas” encompasses a large variety of pathologic entities, this review will focus on the most commonly encountered that may require surgical intervention.

The most common non-neoplastic cysts of pancreas are typically considered to be pancreatic pseudocysts (or early post-pancreatitis acute fluid collections). Their diagnosis is aided (and typically confirmed) by a history of acute or chronic pancreatitis.⁸ Congenital cysts are rare and include those associated with genetic diseases such as autosomal dominant polycystic disease,^9...