Vol.2, No.9, 530-534 (2013) Case Reports in Clinical Medicine
Subcutaneous larva migrans of a sparganum in a
gnathostomiasis-endemic area*
Kunlay anee Akkarac hinorat e1, Pukvaran Udnan1, Kittipong Chaisiri2, Chalit Komalamisra2,
Paron Dekumyoy2, Wallop Pakdee2, Rangsan Praevanich3, Sisuchart Mongkhonmu3,
Dorn Watthanakulpanich2#
1Ban Luang Hospital, Ban Luang, Thailand;
2Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;
#Corresponding Author: dorn.wat@mahidol.ac.th
3Bangkok School of Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
Received 27 September 2013; revised 20 October 2013; accepted 19 November 2013
Copyright © 2013 Kunlayanee Akkarachinorate et al. This is an open access article distributed under the Creative Commons Attribu-
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We report a case of subcutaneous larva migrans
caused by a tape worm (sparganum), a rare and
under-recognized food-borne parasitic zoonosis,
in Nan Province, Northern Thailand. An obese
56-year-old female presented a 3-month history
of an intermittent migrating subcutaneous nod-
ule in the abdomen associated with pain and
itching. Physical examination showed a tubal
resection scar on the lower abdomen with a
swelling and movable irregular, and firm nodule
with ill-defined border at the right lower quad-
ra nt of abdo men. Blood examination showed sli-
ght increase of eosinophil levels (6%). Exci-
sional biopsy showed a viable non-segmented
tape w orm in the subcutaneous tissue identified
by morphological examination and Western blot
technique as a sparganum. Surgical removal is
recommended for a worm in the subcutaneous
connective tissues and superficial m uscles.
Keyw ords: Subcutaneous Larva Migrans;
Sparganosis; Zoonosis; Northern Thailand
Thailand is located in tropical So utheast Asia, a region
that is both hot and humid, which is suitable for the life
cycles of many parasites, including protozoa, helminths
and medical insects. Owing to the specific lifestyles,
primitive culture and local specialty dishes of some Thai
social groups, particularly poor rural communities with
risky food habits, parasitic infections remain a health
problem. Moreover, population migration has introduced
parasites into new localities that may favor their contin-
ued existence and proliferation, such as among available
intermediate hosts. Among humans infected with tissue
helminths, the larval stage may migrate to where the
characteristic eggs are not detected by stool examination,
and be reported as a parasite in human subcutaneous tis-
sues. In Thailand, the clinical manifestation of larva mi-
grans is an intermittent, circumscribed swelling and this
is normally a manifestation of gnathostomiasis, a disease
historically prevalent in the Mekong region of Southeast
Asia [1]. Misdiagnosis may occur when other tissue
helminths, such as spargana, infect humans in areas
where raw dishes of freshwater fish and amphibians are
popular [2]. Correct laboratory identification of the re-
sponsible parasite will inform accurate diagnosis, result-
ing in prompt and appropriate treatment and manage-
An obese 56-year-old female (BMI 27.06), not pale,
without jaundice, showing good consciousness and co-
operation, who had been residing in Ban Luang District,
Nan Province, Thailand, presented with a 3-month his-
tory of a migrating subcutaneous nodule in the abdomi-
nal region, with some related pain and itching. Whenever
she scratched due to the itching, the nodule developed
the appearance of an erythematous acne rash; some
rashes also developed in the area of the swelling. She had
*Competing interests: The authors declare that they have no competing
Copyright © 2013 SciRes. OPEN ACCESS
K. Akkarachinorate et al. / Case Reports in Clinical Medicine 2 (2013) 530-534 531
no fever, cough, or weight loss, and had started meno-
pause in 2011. She used to consume partially cooked or
raw dishes of many kinds of freshwater fish and frogs,
wild boar, and cattle. She did not keep any domestic
animals/pets in her house. Physical examination showed
normal vital signs, no edema in the extremities, and all
body systems within normal limits, except for a tubal
resection scar on the lower abdomen. A swelling and
movable irregular and firm nodule measuring 2 cm in
diameter, with an ill-defined border in the right lower
quadrant of the abdomen was neither tender nor inflamed.
Complete blood count showed unremarkable values, with
a total white cell count of 8.350 cells/mm3 (6% eosino-
phils, 40% neutrophils, 44% lymphocytes, 9% mono-
cytes, 1% basophils), 40% hematocrit, platelets 330,000
cells/mm3. An excisional biopsy showed a viable non-
segmented tapeworm in the subcutaneous tissue, meas-
uring 1.92 cm × 0.18 cm (Figure 1). The pathological
report on the surrounding subcutaneous tissues showed
chronic suppurative granulomatous inflammation with
foreign-body reaction; no residual parasite material was
obtained. The excised parasite was identified by mor-
phological (Figure 2) and Western blot techniques. The
results showed the specimen to be a sparganum in the
family Diphyllobothriidae, for which praziquantel or
niclosamide are effective drugs [3-5]. While surgical
removal of the sparganum was the most effective treat-
ment in this case and there was no swelling and movable
nodule found anywhere for the follow up of the patient.
The identification of the removed worm was the defini-
tive diagnosis, it may not be preferred if the parasite is
embedded deeply in tissues and can invade vital organs
This case illustrates sparganum as a visceral larva mi-
grans that can cause misdiagnosis of gnathostomiasis in
endemic areas such as Thailand. Owing to their similar
life cycles and infective stages, where both worms can
Figure 1. Excisional biopsy of right lower quadrant abdomen
showing sparganum.
Figure 2. Morphology of sparganum. (a) Elongate, cream-
white and ribbon-like unbranched sparganum, measuring 1.92
cm in length and 0.18 cm in width; (b) a candal part with no
internal structures or other morphologic features that can be
distinguished for species identification; (c) an anteroposterior
polarity, called a pseudosucker with no scolex.
inhabit the same group of second intermediate hosts or
paratenic hosts, humans remain a potential target for in-
fection by both sparganum and Gnathostom a, or even
both worms at once. Laboratory investigation can be
used to distinguish between these two helminthic dis-
eases, to facilitate diagnosis and proper treatment. Treat-
ment failure with albendazole can occur, as benzimida-
zoles are not recommended drugs for use with spar-
ganum [3-5]. This case highlights how a migrating sub-
cutaneous nodule of sparganum can be an important
etiologic pathogen of differential diagnosis. It is a chal-
lenge for clinicians in remote areas to perform a tissue
excisional biopsy, where indirect confirmatory tests are
not available. Western blot shows a weakly positive reac-
tion at 35 kDa specific reacting band of specific IgG4
antibodies against antigens derived from Spirometra
erinacei sparganum after investigation of the patient’s
serum (Dekumyoy, personal contact and unpublished
data). Identification after excisional removal of the para-
site in tissue specimens for detection of eosinophilia is a
more reliable approach for confirmation of sparganosis
[7]. In this study, results of the pathological report of the
tissue biopsy did not show any residu al parasitic material,
which could exclude rare sparganosis prolifera of the
budding larvae as new spargana in the tissues. As spar-
ganosis and gnathostomiasis are both food-borne zoono-
tic diseases, they can be exported to other countries via
international travel. Both these helminthic diseases can
spread into non-endemic areas.
Sparganum is the generic name of the plerocercoid,
which is a tissue-migrating larva of canine/feline tape-
worms of the Diphyllobothrium and Spirometra species.
Sparganum refers specifically to larvae of Spirometra
Copyright © 2013 SciRes. OPEN ACCESS
K. Akkarachinorate et al. / Case Reports in Clinical Medicine 2 (2013) 530-534
spp. in humans, which are known to cause sparganosis of
subcutaneous and visceral larva migrans [8]. Spirometra
adult worms inhabit the small intestine of dogs, cats and
wild carnivores, but rarely humans (spirometrosis). Co-
pepods (freshwater crustaceans) are the first intermediate
host for development of procercoid; various kinds of
vertebrates (amphibians, reptiles, birds and mammals)
then serve as the second intermediate host for develop-
ment of plerocercoid, to complete the life cycle [9]. Spo-
radic cases of sparganosis in humans have been reported,
mainly because of their scarcity but also because of the
difficulties around identification; there were only 52
cases of human sparganosis reported in Thailand be-
tween 1943 and 2010 [10]. Although sparganosis is gen-
erally thought to be distributed all over the world, Spi-
rometra spp. seem to be responsible for the larval plero-
cercoid stage and in humans rarely develop to adulthood;
it appears parasitic in muscles or body cavities. However,
ocular and cerebral involvements have been reported in
relation to sparganosis lesions found in Thai patients
particularly cerebral sparganosis accompanied by brain
abscess, seizures, hemiparesis has poor prognosis [10].
The larval plerocercoid can mostly be seen as a white,
string-like creature in the muscles or body cavities of
birds (chickens, ducks), reptiles (snakes), amphibians
(frogs), and small rodents, which are considered to be
important sources of infection. In addition, these hosts
and humans can also be infected by drinking contami-
nated water with cyclops-carrying procercoids, consum-
ing inadequately cooked meat containing the second-
intermediate or paratenic host carrying plerocercoids,
and also suffer penetration of cutaneous tissues from
poultices made of the flesh of frogs or snakes as dress-
ings for open wounds and eye sores [9,11,12]. Lesions
and clinical symptoms of sparganosis have much in
common with those of gnathostomiasis spinigerum; the
subcutaneous migrans is usually found as a migrating
nodule, varying in size, with occasional slow migration.
Gnathostomiasis is an important zoonosis with wide
distribution from tropical to temperate zones; it can be
fatal to humans if vital organs are affected [3]. The dis-
ease is widespread across Ecuador and Mexico in Latin
America [13,14], and Laos, Vietnam and Thailand in
Southeast Asia [2,15]. Gnathostoma spinigerum is par-
ticularly prevalent, yet remains the only etiologic agent
of human infection in Thailand so far [16]. Adult worms
are generally 2 - 3 cm long, with spines covering the
cephalic bulb to the posterior end, and inhabit tumors of
the gastrointestinal wall in fish-eating mammals. Com-
mon intermediate hosts are cyclops and freshwater fish
(eels, catfish, snake-head fish), reptiles (snakes) and
amphibians (frogs), which develop by hatching from
eggs into infective advanced third-stage larvae, which
themselves sometimes may be transferred to paratenic
hosts such as chickens, ducks, or pigs. Humans mostly
get infected accidentally by eating the infected flesh of
intermediate and paratenic hosts, in whom worms do not
develop into the adult stage. There are two other routes
of infection, as well, via skin penetration and prenatal
infection [2]. The most common manifestation is inter-
mittent migratory circumscribed swelling, with associ-
ated redness, pain and itching in the subcutaneous tissues;
this tends to subside and reappear elsewhere near the
original site. In rare cases, the pa tient may suffer seizures,
paralysis, unconsciousness, or even death due to severe
damage of the CNS; invasion of the eye can also result in
visual impairment [17]. Meanwhile, immature worms
have been found using excisional biopsy methods in
some patients, as migratory swelling tracks have been
left behind after the worms’ movement. Although worm
removal is a good method of treating gnathostomiasis, it
remains impractical as it often fails to remove all of the
etiologic worms present. Therefore, indirect investigation
in the laboratory is performed to g ive a tentative diagno-
sis of gnathostomiasis. One method is to use specific
monoclonal antibodies to detect circulating antigens to
the Gnathostoma worm; another is to use Western blot to
detect specific antibodies. However, such tests are not
available in remote areas of Thailand. Indeed, tests like
these are most frequently carried out in university ho spi-
tals, such as the Hospital for Tropical Diseases, Mahidol
University. About 1000 suspected cases are diagnosed
clinically each year after being sent for confirmatory
tests of gnathostomiasis, according to the annual report
of the Faculty of Tropical Medicine [18]. Clinicians
might decide to start treatment with albendazole (800 mg)
for 21 days [19], and observe clinical symptoms with a
follow-up drop in Gnathostoma antibody titer. It is chal-
lenging to perform an excisional biopsy at the swelling
area, as worms can always escape from the swollen mi-
gration tracks. For our patient, who had been residing in
rural areas of Ban Luang District, Nan Province, Thai-
land, an excisional biopsy was attempted, and was suc-
cessful in removing the invading sparganum (Figure 3).
Recently, an alternative treatment with praziquantel (75
mg/kg/day), given in three consecutive doses, has been
attempted and the result was successful for visceral spar-
ganosis [5].
The sparganum can be an important etiologic pathogen
of differential diagnosis in migrating subcutaneous nod-
ules in endemic areas like Thailand. Clinical manifesta-
tions of gnathostomiasis and sparganosis are alike, in
terms of the migration of the immature worm, known as
subcutaneous larva migrans. This remains a cause of
migratory swelling in patients, which is the common
symptoms presented, and is the result of increased glob-
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K. Akkarachinorate et al. / Case Reports in Clinical Medicine 2 (2013) 530-534 533
Figure 3. Post-operation showed no swelling
subcutaneous tissue (arrow) with distended
lower abdomen.
alization and proliferation of food-borne zoonotic dis-
eases. The challenges surround the difficulties of per-
forming tissue excisional biopsies, and indirect confir-
matory tests are not available in remote areas. Rapid and
accurate diagnosis is important for prompt treatment and
appropriate case management, so imported cases can be
dealt with efficiently by physicians in non-endemic areas
and countries.
Informed consent form was required and written by
the patient for the allowance to be published in the jour-
The authors owe very special thanks to the Faculty of Tropical Me-
dicine, Mahidol University for supporting the budgets for field trip sur-
vey. The appreciation goes to Dr. Saravuth Konggarnkha for patholo-
gical examination of the biopsied tissue. Many thanks also to Mr. Paul
Adams for editing the manuscript.
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