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Tumors of Major and Minor Ampullae

Introduction Since both the distal common bile duct and the main pancreatic duct converge at the level of the ampulla, ampullary tumors ( Box 42.1 ) may obstruct two organs, which may lead to early onset of symptoms. However, the potential for early detection has improved the prognosis for neoplasms of the ampulla, especially in comparison with other pancreatobiliary tumors. New techniques that are being used…

Tumors of the Pancreas

Introduction And Classification Probably the most common problems in the diagnosis of pancreatic neoplasms are the distinction of invasive ductal adenocarcinoma from its mimics and the preoperative evaluation of cystic lesions, which are increasingly recognized. Solid, cellular pancreatic neoplasms present a different type of diagnostic challenge. The relative inaccessibility of the pancreas and the potential for complications from biopsies mean that small tissue samples (core biopsy…

Inflammatory and Other Nonneoplastic Disorders of the Pancreas

Introduction This chapter discusses a range of inflammatory and other nonneoplastic diseases of the pancreas, with a focus on variants of chronic pancreatitis that mimic pancreatic neoplasia including autoimmune pancreatitis (AIP) and paraduodenal pancreatitis. In the past, a generic diagnosis of chronic pancreatitis was often sufficient, but with the recent recognition of unique variants, some steroid responsive, the pathologist is required to further subclassify this disorder.…

Benign and Malignant Tumors of the Gallbladder and Extrahepatic Biliary Tract

Acknowledgment We thank Drs. Kerem Ozcan and Aslihan Yavas for their contributions in the preparation of this chapter. Introduction As discussed in other chapters, gallstones and inflammatory disorders constitute the vast majority of biliary tract pathology. Neoplasms and tumor-like lesions (pseudotumors) are relatively rare but form an important category with challenging diagnostic issues. As a result of advances in radiographic modalities and widespread use of laparoscopic…

Infectious and Inflammatory Disorders of the Gallbladder and Extrahepatic Biliary Tract

Introduction The gallbladder is a surgical pathology specimen normally obtained by laparoscopic cholecystectomy or laparotomy. Historically, surgical pathologists have dedicated little time to the gross and microscopic examination of the gallbladder because they have believed that the information derived from them is not relevant to patient care. This persistent lack of interest has hampered our understanding of the broad range of inflammatory conditions of this organ.…

Developmental Disorders of the Gallbladder, Extrahepatic Biliary Tract, and Pancreas

Introduction Developmental, congenital, hereditary, and structural disorders that can affect the gallbladder, extrahepatic biliary tract, and pancreas are listed in Box 37.1 . This chapter focuses primarily on the few disorders that are encountered peripherally or directly in surgical pathology. Hereditary pancreatitis is discussed in Chapter 40 . BOX 37.1 Developmental Disorders and Structural Abnormalities of the Gallbladder, Extrahepatic Biliary Tract, and Pancreas Gallbladder Agenesis Hypoplasia…

Diagnostic Cytology of the Biliary Tract and Pancreas

Introduction Brushing cytology and fine-needle aspiration (FNA) are used to sample lesions in the biliary tract and pancreas. Endobiliary brushing is currently the preferred method of sampling the pancreatobiliary system in patients with a stricture or obstruction without an associated mass. It is also used to screen patients with primary sclerosing cholangitis (PSC). FNA is the most effective procedure for sampling solid and cystic masses of…

Molecular Genetics of Pancreatobiliary Neoplasms

Introduction Cancer is fundamentally a genetic disease caused by inherited germline variants coupled with the accumulation of somatic mutations in oncogenes and tumor suppressor genes. Some patients inherit gene mutations that predispose them to cancer, while others acquire all alterations somatically. In both inherited and sporadic cancers, neoplasms acquire numerous somatic alterations throughout their development; some are driver alterations that play crucial roles in tumorigenesis while…

Gallbladder, Extrahepatic Biliary Tract, and Pancreas Tissue Processing Techniques and Normal Histology

Introduction Disorders of the biliary tract affect a significant portion of the world’s population. More than 95% of biliary tract disease is attributable to cholecystitis and cholelithiasis (i.e., gallstones). It is estimated that about 20 million persons in the United States have gallstones. The annual cost of treatment for gallbladder disease was estimated in 2014 to exceed $4 billion, representing approximately 0.1% of the national health…

Algorithmic Approach to Diagnosis of Pancreatic Disorders

Introduction Normal Histology Microscopically, the pancreas is composed of epithelium (acini, islets, and ducts), connective tissue, and lymphoid tissue. These components may be variably present within any individual pancreatic biopsy, depending on the location and adequacy of the tissue sample. The parenchyma is divided into lobules separated by loose connective tissue septa. Because the pancreas functions as both an exocrine (secretory) and endocrine organ, its parenchyma…

Inflammatory and Neoplastic Disorders of the Anal Canal

Embryology and Anatomy of the Anus and Anal Canal The anal canal forms during the fourth to seventh weeks of gestation after partitioning of the cloaca into the ventral urogenital membrane and dorsal membrane. The epithelium of the superior two-thirds of the primitive anal canal is derived from the endodermal hindgut; the inferior one-third develops from the ectodermal proctodeum. The dentate line, also known as the…

Hematolymphoid Tumors of the Gastrointestinal Tract, Hepatobiliary Tract, and Pancreas

Introduction In 55% to 75% of gastrointestinal (GI) lymphomas, the stomach is the primary site. Lymphoma accounts for 1% to 7% of all gastric malignancies. , Diffuse large B-cell lymphoma and extranodal marginal-zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) are the most common types, with some series having more of the former, and others more of the latter. Other types of lymphoma are quite uncommon,…

Mesenchymal Tumors of the Gastrointestinal Tract

Introduction Although epithelial neoplasms predominate in the tubal gut, a variety of mesenchymal neoplasms may originate from or secondarily involve the gastrointestinal (GI) tract. Given the rarity of these lesions and the fact that many have overlapping histological features, accurate classification can be challenging, especially in the setting of limited endoscopic biopsy material. That said, knowledge of a few key details can help narrow an often…

Neuroendocrine Tumors of the Gastrointestinal and Pancreatobiliary Tracts

Acknowledgment The authors are indebted to Dr. Hulya Sahin Ozkan, Dr. Kerem Ozcan, and Ms. Rhonda Everett for their extensive contributions in the preparation of this chapter. Neuroendocrine Cell System of the Gastrointestinal Tract Neuroendocrine cells in the gastrointestinal (GI) tract altogether constitute the largest endocrine system in the body. In addition to functioning as endocrine cells they have distinctive properties; they also show autocrine, paracrine,…

Epithelial Neoplasms of the Appendix

Mucinous Epithelial Tumors The classification of appendiceal epithelial tumors is shown in Box 28.1 . The classification, nomenclature, and histological criteria of mucinous epithelial tumors in the appendix have been the source of considerable controversy. In particular, mucinous epithelial tumors that penetrate deeply into or through the appendiceal wall and disseminate to the peritoneal cavity, resulting in pseudomyxoma peritonei, were the source of much of this…

Epithelial Neoplasms of the Large Intestine

Introduction The most common neoplasms of the large intestine are adenomas, conventional or serrated in type (see Chapter 22 ). Adenomas are the precursor of most primary malignant epithelial neoplasms of the large intestine. Although abundant clinical, morphological, and genetic evidence suggests that primary epithelial malignant neoplasms are a heterogeneous group of tumors, most clinicians consider these neoplasms together to be colorectal carcinoma. , Much of…

Epithelial Neoplasms of the Small Intestine

Introduction Epithelial neoplasms develop far less frequently in the small intestine than in the colon, despite the fact that the small intestine has a larger epithelial surface area and a higher rate of cellular turnover. Overall, only 2% of all malignant neoplasms of the gastrointestinal (GI) tract occur in the small intestine. In contrast, 57% of neoplasms arise in the colon. A number of hypotheses have…

Epithelial Neoplasms of the Stomach

Introduction Gastric cancer remains an important cancer worldwide and is responsible for over 1 million new cases in 2020, and an estimated 769,000 deaths (equating to 1 in 13 deaths globally), ranking fifth for incidence and fourth for mortality globally. , Over the past 50 years, the incidence and mortality rates of distal gastric cancer have been uniformly decreasing in North America, Europe, and, more recently,…

Epithelial Neoplasms of the Esophagus

Introduction Most benign and malignant neoplasms of the esophagus are epithelial in origin ( Box 24.1 ). Overall, an estimated 17,650 new diagnoses of esophageal carcinoma, and 16,000 deaths, occurred in the United States in 2019. The incidence of esophageal carcinoma has increased in the United States and Europe in the past 30 years, principally because of a marked rise in Barrett’s esophagus (BE)–associated adenocarcinoma. BOX…

Molecular Diagnostics of Tubal Gut Neoplasms

Introduction The genomic revolution is inexorably changing our understanding of nearly all medical conditions, and it is changing our clinical practices in the fields of diagnostic pathology and oncology. Indeed, genomic biomarkers have dramatically improved clinical algorithms for diagnosis, prognosis, treatment, and disease monitoring of cancer. It is now well recognized that all clonal neoplasms result from accumulating alterations in the genome that are usually acquired…