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Pancreas

Nonneoplastic Entities Chronic Pancreatitis Clinical Features Defined by irreversible loss of pancreatic parenchyma and function caused by inflammation Patients present with recurrent attacks of abdominal and back pain and evidence of loss of pancreatic function including exocrine insufficiency (malabsorption and steatorrhea) and diabetes mellitus Alcohol abuse is the leading cause of chronic pancreatitis in Western countries. Other common causes include obstruction of the ducts by biliary…

Hepatobiliary System

Viral Hepatitis Clinical Features Hepatitis A Virus Single-stranded RNA (ssRNA) virus (picornavirus) Transmission route: fecal-oral Incubation: 2 to 6 weeks Self-limited Not associated with chronic carrier state, chronic hepatitis, or hepatocellular carcinoma (HCC) Hepatitis B Virus Partially circular double-stranded DNA virus (hepadnavirus) Transmission route: perinatal, sexual, and parenteral Incubation: 6 to 8 weeks Chronic infection (10%): persistent serum hepatitis B surface antigen (HBsAg) more than 6…

Gastrointestinal System

Esophagus Congenital and Acquired Esophageal Abnormalities Clinical Features Esophageal Ectopias Gastric Affects up to 20% of population Found in cervical esophagus; referred to as inlet patch ( Figure 6.1 ) May produce peptic symptoms in older patients Rare examples of dysplasia or carcinoma reported complicating inlet patches Sebaceous: so-called Fordyce granules Pancreatic Rare in esophagus Can be seen with trisomy 18 or trisomy 13 More often…

Thymus and Mediastinum

Thymic Cyst Clinical Features Uncommon; constitutes less than 10% of mediastinal cysts May be congenital or acquired Found in the anterior mediastinum but may occur in ectopic locations such as neck, pleura, and posterior mediastinum Invariably benign Age range: 20 to 50 years, often asymptomatic; larger cysts can present with cough, dyspnea, and chest pain Acquired thymic cysts are associated with inflammatory processes and have been…

Lung and Pleura

Non-Neoplastic Conditions Congenital Pulmonary Airway Malformation Clinical Features Uncommon developmental anomaly predominantly seen in infants that has features of both immaturity and malformation of the airways and distal lung parenchyma (formerly congenital cystic adenomatoid malformation [CCAM]) Often detected by antenatal ultrasound during the second trimester Reported incidence ranges from 1 in 25,000 to 35,000 pregnancies About 60% of lesions show variable, spontaneous regression during gestation Postnatal…

Head and Neck

Thyroid Gland Granulomatous Thyroiditis (De Quervain Thyroiditis) Clinical Features Also called subacute thyroiditis Presents with clinically marked tenderness of thyroid, fever, sore throat, and malaise most likely related to systemic viral illness Most commonly affects middle-aged women Majority of cases show complete resolution; initial phase often is hyperthyroid (elevated thyroxine [T 4 ] and triiodothyronine [T 3 ] levels); may lead to hypothyroidism, usually euthyroid on…

Skin and Adnexal Structures

Inflammatory Conditions Superficial Perivascular Dermatitis Dermatitis With Minimal Epidermal Changes Superficial Dermatophytosis (Tinea) Clinical Features Caused by three genera of imperfect fungi— Epidermophyton, Trichophyton, and Microsporum —that cause superficial infections involving keratinized tissues such as the cornified layer of epidermis, the hair, and the nails Dermatophytosis involving different anatomic sites named with site-specific terms (scalp-tinea capitis, beard-area-tinea barbae, face-tinea faciei, trunk-tinea corporis, intertriginous areas-tinea cruris, feet…

Special Diagnostic Techniques in Surgical Pathology

Light Microscopy Tissue Processing Overview Fixation Preserves tissues in situ as close to the lifelike state as possible Ideally, fixation will be carried out as soon as possible after removal of the tissues, and the fixative will kill the tissue quickly, thus preventing autolysis Dehydration Fixed tissue is too fragile to be sectioned and must be embedded first in a nonaqueous supporting medium (e.g., paraffin) The…

Pathology of Liver, Small Bowel, and Pancreas Transplantation

Liver Transplantation Liver transplantation is performed in patients with liver failure caused by acute or chronic liver disease, selected hepatic tumors, and some metabolic diseases. Approximately 7000 liver transplants (LT) are performed annually in the United States. The graft survival rate at 5 years is greater than 70%, and the patient survival rate is even higher. The most common types of LT are cadaveric and living…

Gastrointestinal Lymphoma

The gastrointestinal (GI) tract is the most common site of extranodal lymphoma, which should not be a surprise as the GI system contains approximately 70% of the lymphoid tissue and 80% of the plasma cells (most of those being immunoglobulin [Ig] A expressing). Anywhere from 20% to 48% of primary extranodal lymphomas have been reported to occur in the GI tract. Additionally, recent reports provide evidence…

Liver Neoplasms

Primary hepatocellular neoplasms are much less common than metastatic tumors to the liver. The former may arise from either the epithelial or mesenchymal component of the hepatic parenchyma and rarely may also show both lines of differentiation. Hepatocellular neoplasms may be benign or malignant ( Table 18.1 ). The differential diagnosis of a well-differentiated hepatocellular proliferation is typically between focal nodular hyperplasia (FNH), hepatic adenoma (HA),…

Non-Neoplastic Disorders of the Liver

Major Histologic Patterns of Injury Because the liver presents with a relatively small repertoire of responses to injury, there is significant histologic overlap among liver diseases, making specific diagnosis challenging. A pattern-based approach enables the pathologist to generate a relatively short list of differential diagnoses, which can then be distinguished based on histologic findings and available clinical data to establish an informative diagnosis that guides clinical…

Non-Neoplastic and Neoplastic Pathology of the Pancreas

Non-Neoplastic Diseases Developmental Anomalies The three most commonly encountered developmental anomalies of the pancreas in routine surgical pathology practice are pancreas divisum, annular pancreas, and ectopic pancreas. Pancreas Divisum Pancreas divisum occurs in 3% to 7% of the population as a result of failure of the embryonic dorsal and ventral pancreatic buds to fuse properly. The duct of Santorini becomes the major ductal system of the…

Pathology of the Gallbladder and Extrahepatic Bile Ducts

The gallbladder and extrahepatic bile ducts show a limited spectrum of inflammatory and neoplastic disorders, but these disorders are significant because they affect a large proportion of the world’s population. The most common (>95%) is cholelithiasis. Inflammation in the gallbladder secondary to stones presents either as acute or chronic cholecystitis and may lead to significant complications such as empyema, perforation, or fistula. Carcinomas of the gallbladder…

Pathology of the Anal Canal

Anal Anatomic and Histologic Landmarks The anal canal encompasses the distal most 3 to 4 cm of the most distal intestinal tract. It is defined proximally by the palpable upper border of the internal sphincter muscle, which is a continuation of the muscularis propria of the rectum. Distally, the anal canal is limited by the anal verge, an imaginary line where the squamous mucosa of the…

Molecular Testing of Gastrointestinal Neoplasms

Molecular testing of colorectal carcinomaAlthough there are numerous esoteric tests that a molecular pathology laboratory may use on colorectal cancer (CRC) specimens, there are two tests that are the most common and important—assessment of mismatch repair (MMR) integrity and RAS/RAF mutational analysis ( Tables 13.1 and 13.2 ). Assessment of MMR status serves two main functions. First, MMR testing is used to screen for Lynch syndrome.…

Epithelial Neoplasms of the Colorectum

A large variety of neoplasms may occur in the colorectum, reflecting the complexity of this organ and its cellular components. This chapter focuses primarily on those neoplasms arising from the epithelial and neuroendocrine cells of the colorectum. Epithelial neoplasms that arise as a component of a polyposis syndrome are discussed in Chapter 11 . Colorectal Polyps Given the widespread use of colonoscopy as a screening tool…

Gastrointestinal Polyposis Syndromes

Nearly every histologic type of polyp involving the gastrointestinal (GI) tract can occur in a sporadic or syndromic setting. In general, a syndromic diagnosis must be suspected when multiple polyps type are present concurrently or sequentially on surveillance colonoscopy; when the polyps occur at a very young age; when extraintestinal manifestations of particular syndromes are identified; and when there is a family history of similar polyps…

Non-neoplastic Disorders of the Colon

Mucosal biopsies from the colon are obtained most commonly (1) in acutely symptomatic patients with the possibility of an ischemic, infectious, or drug-induced colitis; (2) when graft-versus-host disease (GVHD) needs to be ruled out; or (3) in those with chronic symptoms in whom the main consideration is inflammatory bowel disease (IBD). In other instances, patients with diarrhea and normal colonoscopy results are biopsied to rule out…