A 77-year-old woman with chronic iron deficiency anemia had a
medical examination in May 2002. She was diagnosed as having anisakiasis after
upper endoscopy of the antrum of the stomach, and a worm was removed. Three
years later, an upper endoscopy showed several worms in the first and second
portions of the duodenum, but there were no symptoms. Ten live worms were
removed using standard biopsy forceps and were identified by microscopic
examination as hookworm (Ancylostoma duodenale).
Magnified endoscopy clearly revealed the internal organs of the
hookworm sucking blood from the duodenal mucosa, as well as whitish erosion
with slow oozing at the anchorage point of the hookworm. It was noted that the
conventional endoscopic images of the hookworm were similar to those of
Anisakis simplex, but the magnified endoscopic images
were clearly different ([Fig. 1]).
Fig. 1 Comparison of endoscopic
images of Ancylostoma duodenale and
Anisakis simplex. a
Conventional endoscopic image of A. duodenale.
b Magnified endoscopic image of the upper part of the
body of A. duodenale. A long esophagus, intestine, and
ovary with eggs are seen. The anchorage point of the worm shows whitish erosion
with slow bleeding from the duodenal mucosa. c Magnified
image of the middle part of the body of A. duodenale.
The intestine and ovary with eggs are seen. d
Conventional endoscopic image of two A. simplex worms.
e Magnified endoscopic image of the upper part of the
body of two A. simplex worms. The anchorage point of
the worm is seen as a slightly red swelling of the mucosa without bleeding.
f Magnified image of the middle part of the body of
A. simplex. Translucent white bodies are visualized
but the internal organs cannot be differentiated.
Examination of a stool sample by a formalin-ethyl acetate
concentration technique revealed hookworm eggs. A single dose of pyrantel
pamoate (500 mg) was administered. Two weeks later, upper endoscopy
showed clearance of the worms, and 1 month later, examination of a fresh stool
sample revealed no hookworm eggs.
Endoscopy_UCTN_Code_CCL_1AB_2AZ_3AZ
