Anatomy of
Pancreas and
Congenital
Anomalies
OBJECTIVES• To explain about anatomy of pancreas:
– Gross : blood supply, lymphatic drainage, innervations, ducts system, embryology– Histology : exocrine, endocrine
• To explain about congenital anomalies of pancreas:1. Agenesis2. Pancreas Divisum3. Annular Pancreas4. Ectopic Pancreas5. Congenital Cysts
Anatomy of Pancreas
Gross Histology
GROSS ANATOMY OF PANCREAS• A gland with both exocrine and endocrine functions.• 15-25 cm long• 60-100 g• Location: retro-peritoneum, 2nd lumbar vertebral level• Extends in an oblique, transverse position• Parts of pancreas: head, neck, body and tail
BLOOD SUPPLIES & INNERVATIONS
Arterial Supply:– splenic artery– pancreaticoduodenal arteries
Venous Drainage: Suprapancreatic PV Retropancreatic PV Splenic vein Infrapancreatic SMV
• Ultimately, drains into portal vein
Innervations:• Sympathetic fibers (from the splanchnic nerves)• Parasympathetic fibers (from the vagus)
DUCTS OF PANCREAS
• The pancreatic duct begins in the tail of pancreas.• Joins CBD at the Ampulla of Vater.• 2 – 4 mm in diameter, 20 secondary branches• Lesser duct (Santorini) drains superior portion of head
and empties separately into 2nd portion of duodenum
• Has rich periacinar networks that drain into 5 nodal groups:– Superior nodes– Anterior nodes– Inferior nodes– Posterior PD nodes– Splenic nodes
LYMPHATIC DRAINAGE
HISTOLOGY OF PANCREAS
• Pancreatic acini + duct system.• Produces digestive enzymes
(amylase, trypsin, lipase) and alkaline fluid.
Exocrine Parts
Endocrine Parts
• Islets of Langerhans (pancreatic islets)
• Regulator of glucose, lipid, protein homeostasis.
• b cells at central– Produce insulin
• a cells peripheral– Produce glucagon
• g cells peripheral– Produce
somatostatin
ISLET OF LANGERHAN
NORMAL EMBRYOLOGY• The openings of two
ducts carried into line with each other.
• Two parts of the gland fuse to form one pancreas.
• Dorsal pancreatic duct becomes the accessory pancreatic duct.
• Duct of ventral bud forms the main pancreatic duct.
• Terminal parts of branching ducts form pancreatic acini.
NORMAL EMBRYOLOGY
CONGENITAL DISEASES
Agenesis •Highest mortality rate
Pancreas Divisum •Most common
Annular Pancreas
Ectopic Pancreas
Congenital Cysts
Agenesis• Characterized by:
– absence of a critical mass of pancreatic tissue or, in rare cases, totally absent.
• Cause:– Genetic mutation of PDX1 gene,
located on chromosomal locus 13q12.1
• Normal pancreatic development requires pancreatic duodenal homeobox 1, a homeodomain transcription factor.
• Severity depends on amount of functional pancreatic tissue present.
PANCREAS WITH ABSENT BODY AND TAIL
Associated disease:• Pancreaticobiliary duct anomalies – can lead to acute/chronic
pancreatitisSymptoms:• Abdominal pain• Diabetes (dorsal pancreas agenesis)• Lipid-rich stool (caused by defect of pancreatic enzymes)Exam and Tests:• Abdominal ultrasound• Abdominal CT scanManagement:• treatment of the diabetes and exocrine deficiency, when present. • Infusion of subcutaneous insulin, administration of pancreatic
enzyme.Prognosis:• Variable, depending on the quality of treatment received.
Pancreas Divisum• The duct systems of the
fetal pancreatic primordia fail to fuse.
• most common birth defect.• The cause of the defect is
unknown.• Many cases go undetected.• Pathogenesis:
– The ventral bud failed to fuse with dorsal bud during fetal development.
Clinical features: • Abdominal pain and swelling, nausea or vomiting.• Note: symptoms absent without pancreatitisExams and Tests:• Abdominal ultrasound• Abdominal CT scan• Amylase and lipase blood testTreatment:• Surgery.Complication:• PancreatitisPrognosis:• The outcome is usually good.
Annular Pancreas• A ring of pancreatic tissue
that completely encircles the duodenum.
• Pathogenesis:– May occur when the ventral bud
splits (become bifid), the two segments may encircle the duodenum .
ANNULAR PANCREAS
Annular Pancreas• Symptoms:
Newborns spit up more than normal, do not drink enough milk Adult fullness after eating, nausea or vomiting
• Symptoms occur when the ring of pancreas squeezes and narrows the small intestine.
• Conditions that may be associated with annular pancreas include:– Down syndrome– Excess amniotic fluid during pregnancy (polyhydramnios)– Other congenital gastrointestinal problems– Peritonitis
Exams and Tests:• Abdominal ultrasound• Abdominal x-rayTreatment:• Surgical bypass of the blocked part of the duodenum.Prognosis:• Good outcome with surgery.Complications:• Obstructive jaundice• Pancreatic cancer• Peptic ulcer• Perforation (tearing a hole) of the intestine due to obstruction
Annular Pancreas
Ectopic Pancreas• also known as heterotopic pancreatic tissue.• condition where pancreatic tissues lie outside and separate
to pancreatic gland. • Most are completely asymptomatic.• Common sites:
– Duodenum– Jejunum – Ileum– Meckel’s Diverticulum (remnant of yolk sac)
Symptoms:• Usually non-specific• Abnominal pain & dyspepsia
Diagnosis:• GI endoscopy
Complication:• Intestinal obstruction• Carcinoma of the ectopic pancreatic tissue
Treatment:• Surgery if symptomatic
Ectopic Pancreas
Congenital Cysts• Results from anomalous development of the
pancreatic ducts.• Morphology: – unilocular cysts, range from 5cm in diameter.– Lined by either uniform cuboidal or flattened
epithelium and are enclosed in a thin, fibrous capsule.
– Contains clear serous fluid – important point from pancreatic cystic neoplasms (which is mucinous)
CONGENITAL CYSTS
Symptoms:• Abdominal swelling• Palpable mass• Vomit
Exams and Tests:• Ultrasonography
Management:• Surgery
Congenital Cysts
SUMMARY• There are five congenital diseases, agenesis, pancreas
divisum, annular pancreas, ectopic pancreas, and congenital cysts.
• The most common is pancreas divisum.• Agenesis has the highest mortality rate.• All treatments are via surgery except in agenesis,
insulin infusion (and other pancreatic secretion components) is needed.
• Polyhydramnios can occur in annular pancreas cases.• Cancer mostly occurs in the head of pancreas.
REFERENCES• Textbook of Robbins Basic Pathology• Textbook of Gray’s Anatomy• www.healthline.com • www.medscape.com
QUESTIONS1
1. The following are congenital diseases of pancreasA. Congenital cystsB. Pancreatic divisumC. Heterotopic pancreatic tissueD. AgenesisE. Annular pancreas
TTTTTC. Other name for Ectopic Pancreas
QUESTIONS
2. Pancreas divisum is the most common congenital disease. T/F
1
T
QUESTIONS
3. Annular pancreas is the incomplete fusion of the ducts of pancreas during fetal development. T/F
1
FPancreas divisum incomplete fusionAnnular pancreas encircling duodenum
QUESTIONS
4. Congenital cysts can be managed by cystectomy. T/F
1
T
QUESTIONS
5. Common sites for ectopic pancreas areA. JejunumB. Meckel’s diverticulumC. CaecumD. RectumE. Ileum
1
TTFFT
THANK YOU