Page 554 - Textbook of Pathology, 6th Edition

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Chapter 20 The Gastrointestinal Tract
Chapter 20

OESOPHAGUS the muscularis propria). However, oesophageal atresia and
tracheooesophageal fistula are relatively more common.
NORMAL STRUCTURE OESOPHAGEAL ATRESIA AND TRACHEO-OESO-

The oesophagus is a muscular tube extending from the PHAGEAL FISTULA. In about 85% of cases, congenital
pharynx to the stomach. In an adult, this distance measures atresia of the oesophagus is associated with tracheo-
25 cm. However, from the clinical point of view, the distance oesophageal fistula, usually at the level of tracheal bifur-
from the incisor teeth to the gastro-oesophageal (GE) junction cation. For survival, the condition must be recognised and
is about 40 cm. The region of proximal oesophagus at the corrected surgically within 48 hours of birth of the newborn.
level of cricopharyngeus muscle is called the upper oesophageal Clinically, the condition is characterised by regurgitation of
sphincter, while the portion adjacent to the anatomic gastro- every feed, hypersalivation, attacks of cough and cyanosis.
oesophageal junction is referred to as lower oesophageal Death usually results from asphyxia, aspiration pneumonia
sphincter. and fluid-electrolyte imbalance.
Morphologically, the condition is recognised by cord-like
Histologically, the wall of the oesophagus consists of non-canalised segment of oesophagus having blind pouch
mucosa, submucosa, muscularis propria and adventitia/ at both ends.
serosa.
The mucosa is composed of non-keratinising stratified MUSCULAR DYSFUNCTIONS
squamous epithelium overlying lamina propria except at the
lower end for a distance of 0.5 to 1.5 cm. The basal layer of These are disorders in which there is motor dysfunction of
SECTION III
the epithelium may contain some melanocytes, argyrophil the oesophagus, manifested clinically by dysphagia. These
cells and Langerhans’ cells. At the lower end of the include achalasia, hiatus hernia, oesophageal diverticula, and
oesophagus, there is sudden change from stratified webs and rings.
squamous epithelium to mucin-secreting columnar
epithelium; this is called the junctional mucosa. Achalasia (Cardiospasm)
The submucosa consists of loose connective tissue with Achalasia of the oesophagus is a neuromuscular dysfunction
sprinkling of lymphocytes, plasma cells, and occasional due to which the cardiac sphincter fails to relax during
eosinophil and mast cell. Mucus-producing glands are swallowing and results in progressive dysphagia and
scattered throughout the submucosa.
The muscularis propria is composed of 2 layers of smooth dilatation of the oesophagus (mega-oesophagus).
muscle—an inner circular coat and an outer longitudinal coat. ETIOLOGY. There is loss of intramural neurons in the wall
Systemic Pathology
The proximal portion of oesophagus contains skeletal muscle of the oesophagus. Most cases are of primary idiopathic
fibres from cricopharyngeus muscle. The parasympathetic achalasia which may be congenital. Secondary achalasia may
nerve supply by the vagus nerve is in the form of extrinsic occur from some other causes which includes: Chagas’ disease
and intrinsic plexuses. (an epidemic parasitosis with Trypansoma cruzi), infiltration
The adventitia/serosa is the outer covering of into oesophagus by gastric carcinoma or lymphoma, certain
oesophagus. Serosa is present in intra-abdominal part of viral infections, and neurodegenerative diseases.
oesophagus only, while elsewhere the perioesophageal
adventitia covers it. MORPHOLOGIC FEATURES. There is dilatation above
The major functions of oesophagus are swallowing by the short contracted terminal segment of the oesophagus.
peristaltic activity and to prevent the reflux of gastric contents Muscularis propria of the wall may be of normal thickness,
into the oesophagus. hypertrophied as a result of obstruction, or thinned out
due to dilatation. Secondary oesophagitis may supervene
CONGENITAL ANOMALIES
and cause oesophageal ulceration and haematemesis.
Congenital anomalies of the oesophagus are uncommon and
are detected soon after birth. These include a few rare Hiatus Hernia
anomalies such as agenesis (congenital absence of
oesophagus) which is incompatible with life, duplication of Hiatus hernia is the herniation or protrusion of part of the
oesophagus (double oesophagus) and congenital stenosis (i.e. stomach through the oesophageal hiatus of the diaphragm.
fibrous thickening of the oesophageal wall and atrophy of Oesophageal hiatal hernia is the cause of diaphragmatic