Pancreatic and Biliary Pathology PDF

PANCREATIC AND BILIAR PATHOLOGY Gallbladder: anatomy pancreas : gladula insulina y glucagon and histology ▪ Pear shaped saccular structure for bile storage in gallbladder fossa of posterior right hepatic lobe ▪ Attached to liver by l...

PANCREATIC AND BILIAR PATHOLOGY Gallbladder: anatomy pancreas : gladula insulina y glucagon and histology ▪ Pear shaped saccular structure for bile storage in gallbladder fossa of posterior right hepatic lobe ▪ Attached to liver by loose connective tissue and to duodenum by cholecystoduodenal ligament ▪ Has fundus, body and neck ▪ Has mucosa, muscularis propria and serosa on free surface ▪ No muscularis mucosa or submucosa is present ▪ Surface epithelium:Composed of single layer of uniform, tall columnar cells with basal nuclei, indistinct nucleoli, pale cytoplasm due to sulfomucins.  vasicula amarilla grassa Cholesterolosis benigna accumulo de cholesterol ▪ Asymptomatic ▪ Due to accumulation of cholesterol esters and triglycerides in subepithelial macrophages and gallbladder epithelium Gross description Yellow, flat deposits on mucosal surface, focal or diffuse May have speckled appearance ("strawberry gallbladder") Microscopic (histologic) description Foamy macrophages in lamina propria and epithelium cholesterol cellulas vacias como el higado  polyp = benignos / mujeres Cholesterol polyp ▪ Most common benign polyp (50 - 90%) ▪ Morphologic variation of cholesterolosis ▪ Usually women (75%), 40 - 50 years old inflamacion : colecestitis Gross description 4 - 15 mm, yellow, soft, pedunculated, often multiple Microscopic (histologic) description Mucosal projections with lipid laden macrophages covered by normal gallbladder epithelium lleno de cellulas de grassa Cholecystitis acute ▪ Present in 5 - 10% of cholecystectomy specimens ▪ Either gallstone associated (acute calculous cholecystitis) or not (acute acalculous cholecystitis) ▪ 10% perforate without treatment Gross description Enlarged, distended gallbladder Congested vessels ("angry red color"), serosal and mucosal exudate, thickened wall with edema and hemorrhage Ulcers with blood clot, pus and bile Microscopic (histologic) description ulceracion = hemoragia Initially edema, congestion, hemorrhage, fibrin deposition in and lynfocytos neutrophylos around muscular layer Later mucosal and mural necrosis with neutrophils Variable reactive epithelial changes resembling dysplasia Chronic cholecystitis lynfocytos = inflammacion ▪ Most cholecystectomies are performed for chronica intermittent obstruction of gallbladder neck / cystic duct by gallstones, causing biliary colic ▪ 95% are associated with cholelithiasis ▪ 75% women, ages 40+ Microscopic (histologic) description Mild chronic inflammation with Rokitansky- Aschoff sinuses, granulomas (from ruptured Rokitansky-Aschoff sinuses), smooth muscle hypertrophy Rokitansky-Aschoff sinuses: tubular structures present within the wall in 90%, likely herniations or diverticula due to increased intraluminal pressure; called Luschka ducts if subserosal.  scamoso muy poco freq glandula normelmente mas fino conductos Gallbladder carcinoma ▪ Relatively uncommon ▪ Age 60+ years (mean 72 years), 75% women, usually not resectable ▪ Metastases to peritoneum and liver, pericholedochal lymph nodes of lesser omentum, occasionally to lungs and pleura ▪ 90% are adenocarcinoma, 5% squamous cell or adenosquamous, 5% undifferentiated Gross description Fibrosis and thickening of wall, may be papillary and diffuse Tumor may not be obvious, although liver spread is usually evident at time of diagnosis escrecienca de tumor ulcerando Microscopic (histologic) description Infiltrative (diffuse thickening and induration of wall) or exophytic (irregular, cauliflower mass that grows into lumen and invades wall) Well formed glands in papillary architecture with wide lumina, atypical cuboidal cells, high grade May extend to Rokitansky-Aschoff sinuses (but this does not signify deep invasion)  Pancreas: anatomy ▪ 15 cm long, 60 - 140 g ▪ Shape is compared to letter J turned sideways, with loop of J around the duodenum ▪ Divided into head, body and tail ▪ Retroperitoneal organ ▪ Anterior body of pancreas touches posterior wall of stomach ▪ Posterior of pancreas touches aorta, splenic vein and left kidney ▪ Pancreatic tail extends to the splenic hilum Pancreas: histology Exocrine pancreas Endocrine pancreas  Annular pancreas ▪ Incidence 1 per 12,000 - 15,000 live births ▪ Head of pancreas circles duodenum as a collar and may constrict lumen ▪ Due to failure of ventral bud to rotate properly ▪ Associated with Down syndrome, esophageal atresia, imperforate anus, congenital heart disease, malrotation of the midgut dduodeno dentro del pancreas = annular Pancreas divisum partido con 2 conductos ▪ Most common congenital anomaly of the pancreas (3 - 10% of population) ▪ Most patients are asymptomatic ▪ Incomplete fusion of dorsal and ventral pancreatic ducts causes separation of ventral and dorsal pancreas as a double pancreas ▪ Two ductal systems drain separately to two duodenal papillae en 2 partes may be risk factor for recurrent acute pancreatitis ▪ Duct of Santorini provides main drainage ▪ Diagnose by imaging studies such as ERCP variente anatomica Acute pancreatitis Definition / general Acute onset of abdominal pain due to enzymatic necrosis and inflammation of pancreas hemorragia de la piel necrosis de la glandula = ireversible obstruction de los conductos  Gross description Microscopic (histologic) description ▪ Swollen, indurated, edematous or hemorrhagic / necrotic, yellow nodules represent fat necrosis in pancreas, mesenteric and peritoneal fat como en el pulmon Chronic pancreatitis ▪ Repeated attacks of pancreatic inflammation with loss of pancreatic parenchyma and replacement with fibrosis, variable pain and symptoms of pancreatic insufficiency (malabsorption, diabetes) ▪ May simulate or coexist with pancreatic carcinoma pequenas glandulas Gross description Hard, shrunken, dilated ducts, visible calcified concretions (protein plugs), pseudocysts common fibrosis Microscopic (histologic) description Loss of acini and ductal tissue with relative sparing of islets, irregularly distributed bland periductal fibrosis, variable obstruction of pancreatic ducts of all sizes Chronic inflammation around lobules and ducts Dilated ducts with concretions Ductal epithelium is atrophic, hyperplastic or undergoes squamous metaplasia Exocrine tumors : Ductal adenocarcinoma muy agresivo Definition / general An infiltrating epithelial neoplasm with glandular (ductal) differentiation Poor prognosis: 5 year survival rate 6% ; 90% die within 1 year Derived from pancreatic ductal epithelia en la cabeza del pandreas Sites Head of the pancreas: 60% - 70%; body: 5 - 15%; tail: 10 - 15% Head tumors: 50% have distention of biliary tree and progressive jaundice; 85% have extension beyond pancreas at diagnosis Body / tail tumors: typically larger at diagnosis since these tumors do not cause symptoms until late; 25% have peripheral venous thrombi; metastases common Genetic evolution of pancreatic cancer DISPLASIA GRADO 2 DISPLASIA GRADO 3 displasia grado 1 Obesidad = mama lo que produce inflamacion Gross description pancreas rosa ; tumor = blanca White gray, sclerotic, poorly defined mass 25% of head tumors extend to duodenal wall If advanced, may be difficult to determine site of origin between pancreas, ampulla and common bile duct 20% have multiple tumors Microscopic (histologic) description Infiltrating well to poorly formed glandular / ductal structures surrounded by remarkably desmoplastic stroma Perineural invasion present in 90%, typically with better differentiated glands TNM histologic grading system, recommended by College of American Pathologists, is based on the extent of glandular differentiation: G1=well differentiated, ( > 95% tumor composed of glands), G2=moderately differentiated (50 - 95% glands), G3=poorly differentiated ( < 49 glands), G4=no or minimal differentiation Klöppel grading system: G1 (well) to G3 (poorly differentiated) based on four criteria: degree of glandular differentiation, mucin production (lower grade more mucin), mitosis ( < 5/10HPF, 6-10/10HPF, > 10/10HPF) and nuclear features Background pancreas may show high grade PanIN, atrophic changes, chronic inflammatory infiltrate, fibrosis, ductal dilation beyond tumor mass infiltrado por el tumor indicador de infiltracion Pancreas Acinar cell carcinoma Definition / general Malignant epithelial neoplasm composed of cells with morphological resemblance to acinar cells 1 - 2% of pancreatic malignancies Gross description Well circumscribed, soft / fleshy (since minimal stroma) with fibrous septa, large (mean 11 cm), hemorrhage and necrosis common celulas tumorales nucleo prominente muchas mitosis invasion de vaso Microscopic (histologic) description Highly cellular with minimal stroma and no desmoplasia Solid, nesting, glandular or acinar patterns Monotonous, uniform polarized cells with abundant eosinophilic granular apical cytoplasm due to zymogen granules (scanty in solid tumors), basal nuclei and single prominent nucleoli Moderate nuclear atypia, variable mitoses, no mucin Vascular invasion often present Pancreas Neuroendocrine neoplasms Definition / general ▪ 1 - 2% of all pancreatic neoplasms ▪ Can be either well differentiated tumors or poorly differentiated carcinomas ▪ Neoplasms which express neuroendocrine markers (synaptophysin, chromogranin A, CD56) ▪ Functional tumors are associated with elevated serum hormone levels and are associated with a clinical hormonal syndrome ▪ Insulinoma:Most common functioning pancreatic neuroendocrine tumor Essential features Well differentiated neuroendocrine tumors: -"Salt and pepper" nuclei -Cellular uniformity, central ovoid nucleus -A variety of architectures: ribbons / trabeculae, nesting, glands, gyriform, pseudorosettes Gross description Firm, commonly well circumscribed, homogeneous Microscopic (histologic) description ▪ Well differentiated neuroendocrine tumors: Organoid architecture: solid nests, trabeculae, gyri, cords, festoons, ribbons, glandular, acinar, cribriform Small to medium cells with eosinophilic and finely granular cytoplasm; nuclei are uniform, central, round / oval, with "salt and pepper" (finely stippled) chromatin; no / inconspicuous nucleolus Rich vascular network Amyloid deposition in insulinomas Psammoma bodies in somatostatinomas ▪ Poorly differentiated neuroendocrine carcinomas: Sheets or nests of atypical cells with pleomorphic, hyperchromatic nuclei and abundant mitotic figures "Salt and pepper" chromatin is lost Necrosis often present necropsias May be small cell (molding nuclei, scant cytoplasm) or large no se puede quitar un pancreas de una personna cell (abundant amphophilic cytoplasm; may also have visible nodula pequeno = tumor nucleoli) mas importante = la gravida de los tumores del pancreas cholecistitis = dolores (palpacion) exploracion : bloober positivo = apendicitis murphy positivo = inflamacion de la vesicle