A 15-year-old boy attended our outpatient clinic for recurrent lower
abdominal pain. He did not have any remarkable medical and family history. The
cramping abdominal pain was localized around the right lower quadrant region,
and he had no other gastrointestinal symptoms. He often ate raw fish, and
sometimes his feces contained noodle-like material. Serum chemistries were all
within the normal ranges, and the hematologic examination revealed mild
microcytic hypochromic anemia (hemoglobin 12.4 g/dL, hematocrit
36.3 %, MCV 77.9 fL, MCH 26.7 pg). No eggs were
seen in the stool examination.
Colonoscopy revealed many shallow, oval-shaped aphthoid ulcers with
edema, located in the distal ileum up to the proximal ascending colon ([Fig. 1]). The histologic examination revealed chronic
inflammation with superficial ulceration, several inflamed crypts with
abscesses, and eosinophilic infiltration ([Fig. 2]). The microscopic examination of lavage
fluids during colonoscopy revealed a large quantity of oval-shaped, operculated
eggs ([Fig. 3 b]), and the noodle-like
material was identified as proglottides of Diphyllobothrium
latum ([Fig. 3 a]). A single dose of
praziquantel 600 mg was given for treatment of D.
latum infection. A repeat colonoscopy revealed the ulcers had healed, and
the patient’s feces were found to be egg-free after 1 month. He also had
no more abdominal pain.
Fig. 1 Initial colonoscopic
findings. a Multiple shallow aphthoid ulcers with
mucosal erythema in the distal ileum. b Similar ulcers,
3 – 5 mm in size, in the proximal ascending
colon.
Fig. 2 Histologic examination
(hematoxylin and eosin, magnification × 200) shows chronic
inflammation with superficial ulceration, multiple areas of cryptitis with
abscess formation, and eosinophilic infiltration.
Fig. 3 Gross and microscopic
appearance of Diphyllobothrium latum:
a a proglottid
(length = 20 cm); and b
operculated eggs.
Diphyllobothriasis is a disease that occurs worldwide, with a higher
prevalence in areas of the northern hemisphere where raw or partially cooked
fish is commonly eaten [1]
[2].
Although there have been several reports of colonoscopic detection of
D. latum infection, there have been no reports of
cases of D. latum infection with colonic ulcers
identified by colonoscopic examination, as in our patient [3]
[4]. In the absence of discharge of
proglottides or eggs in the feces, it may be difficult to differentiate this
lesion from chronic inflammatory conditions such as infectious colitis and
ulcerative colitis. Keeping in mind the size and shape of the colonic ulcers,
it is possible they may be caused by the action of the “sucking
grooves” of the intact scolex of the worms.
With the increasing consumption of raw fish around the world,
endoscopists should consider parasite infections, including those caused by
D. latum, in patients with colonic ulcers and
recurrent, nonspecific abdominal pain.
Endoscopy_UCTN_Code_CCL_1AD_2AZ
