Brajendra Baser et al
Primary Orbital Hydatid Cyst
1Brajendra Baser, 2Shenal Kothari, 3Shreya Thatte, 2Vishal Munjal, 4Arvind Kinger
1Professor and Head, Department of ENT, SAIMS Medical College, Indore, Madhya Pradesh, India
2Associate Professor, Department of ENT, SAIMS Medical College, Indore, Madhya Pradesh, India
3Associate Professor, Department of Ophthalmology, SAIMS Medical College, Indore, Madhya Pradesh, India
4Assistant Professor, Department of ENT, SAIMS Medical College, Indore, Madhya Pradesh, India
Correspondence: Brajendra Baser, Professor and Head, Department of ENT, SAIMS Medical College, Indore-Ujjain State
Highway, Bhanwarsala, Sanwer, Indore, Madhya Pradesh, India, Phone: +91-0731-4064080, Fax: +91-0731-2513392
The authors want to highlight the importance of clinical, radiological and histopathological evaluation in unilateral proptosis. A 17-year-
old male presented with left progressive nonpulsatile proptosis, lateral gaze diplopia and decreased visual acuity. It was diagnosed as
orbital hydatid cyst on CT scan and MRI. The patient was successfully operated with near total recovery of the vision. Radiological
investigation showed a circumscribed cystic lesion lateral to orbit separate from the lacrimal gland. Intraoperative cysts and postoperative
histopathology confirmed the primary orbital hydatid cyst.
Although rare there is always a possibility of a primary hydatid in patients with unilateral proptosis, restricted eye movements and
lateral decreased visual acuity. This is possible even when the Casoni’s test is negative. Surgical excision with postoperative albendazole
is the effective treatment for the cure of disease.
Keywords: Hydatid cyst, Orbital hydatid cyst, Nonpulsatile proptosis.
Hydatid disease, a parasitic infectious disease caused by
larval stage of Echinococcus granulosus. It has three host
epidemiological chain of sheep, dog and human. Humans
are intermediate hosts with hydatid cyst affecting almost all
the organs. Liver and lungs are most commonly affected.
Here we present a rare case of sero-negative hydatid cyst
affecting the orbit diagnosed on the basis of MRI and treated
by surgery followed by chemotherapy.
A 17-year-old male presented with complaints of progressive
painless nonpulsatile proptosis of left eye since 8 months
and reduced vision since 5 months.
Ophthalmic examination revealed a slight eccentric non-
reducible inferomedial proptosis of left eye and measured
11.2 mm by Hurtel’s exophthalmometer with normal
anterior segment. Lateral movement of the left eye were
restricted and visual acuity reduced to finger counting. There
was a nonfluctuant swelling at the lateral canthus of left
eye. Fundus examination showed a vertically oval disk with
hyperemia and blurred margins (Fig. 1). The blood vessels
were stretched and tortuous. There were signs of macular
edema with clear media in the posterior segment.
CT scan revealed a nonenhancing, lobulated well
circumscribed cystic mass with watery content and separate
from the lacrimal gland.
MRI also confirmed the findings showing that the cyst
had a hyperdense rim with septa running through the cyst
Fig. 1: Fundus picture showing a vertically oval disk with hyperemia
and blurred margins
Fig. 2: Cyst with hyperdense rim and septa running through the cyst
Primary Orbital Hydatid Cyst
Otorhinolaryngology Clinics: An International Journal, May-August 2011;3(2):132-134 133
(Fig. 2). Chest X-ray and abdominal ultrasonography was
normal. There was no lymphadenopathy. The routine blood
counts were normal, stool and urine examination did not
show any abnormality and the Casoni’s test was negative.
Patient was taken for cyst excision. Incision was given
at the inferolateral orbital margin and the soft tissue showing
excessive fibrosis was dissected from the bony orbital wall.
The cyst wall was dissected away from the lateral rectus
muscle. Multiple daughter cysts (Fig. 3) within the primary
cyst extending to the posterior part of the eye ball which
were identified and dissected out taking care that they do
not rupture. The bony lateral orbital wall was split to remove
the cysts intact, and was later plated. The wound was
thoroughly washed with hypertonic saline to prevent any
recurrence or toxic reaction due to accidental spill of the
fluid containing the scolices of the Echinococcus. The
excised sample was sent for histopathology (Fig. 4) which
confirmed the diagnosis of hydatid cyst.
The patient was kept on broad spectrum systemic
antibiotics, antiinflammatory drugs and tablet albendazole
for next 2 weeks at a dose of 400 mg twice daily. He was
followed up for next 6 months and was completed
asymptomatic. The papilloedema subsided and the visual
acuity recovered to 6/18, although diplopia persisted on left
Hydatid disease is caused by the development in man, acting
as an intermediate host, of the cystic larval form of
Echinococcus granulosus. It is one of the commonest parasitic
affection in the temporate climate of the world.
Orbital hydatidosis represents a quite rare clinico-
pathologic entity. It can either be primary, where cyst or cysts
are solely located into the orbital cavity (as in our case) or
secondary, when orbital lesions are a part of disseminated
multiorgan systemic disease. The usual strains responsible
for orbital cysts are E. granulosus and E. multicularis,
although E. oligarthrus has been isolated in cases from South
and Central America.
Huilgol1 reported the incidence of orbital cyst from 0.7
to 1 % of all orbital tumors but in highly endemic areas,
orbital hydatid cysts have been reported to represent up to
25.8% of all cystic orbital lesions.2
Orbital hydatid cysts are solitary lesions in the vast
majority of cases, but there are reports in the literature of
multiple intraorbital cysts, a phenomenon which occurs in
less than 5% of patients with orbital hydatid cysts.3
The most commonly presenting clinical symptoms and
signs of orbital Echinococcosis are: Nonpulsatile, nontender
exophthalmos (as in our case), visual disturbances,
papilledema, diplopia chemosis, eyelid edema, conjunctivitis
and hypopyon.4 The mean duration of symptoms has been
reported to vary between 3 months and 2 years.5 In our cases,
the duration of symptoms was 2 months.
In regards to the anatomic location of the intraorbital
hydatid cysts, various orbital locations have been described.
It is well accepted that there is a predilection for the
superomedial and superolateral orbital areas. Interestingly,
Talib, in his report, stated that left-sided lesions were more
common than right-sided ones; due to the fact that left,
common carotid artery arises directly from the summit of
the aortic arch.6
These lesions may be diagnosed by various imaging
techniques. On CT scan the typical characteristic feature of
the ‘water-lily’ sign of Echinococcal cysts in other locations
may or may not be present in the orbital cysts. The MRI is
superior in the detection of the lesion and the delineation of
its relationship to the adjacent ocular structures. Upon MRI
examination, the cystic lesion appears low signal on T1W
images, high signal on T2W images, capsular and peri-
capsular soft tissue enhancement, and the capsule is seen as
a hypointense rim surrounding the mass on T2W images.7
Because of the integrity of the cyst wall in the orbit, the
serologic test results may be inconsistently positive in 50%
Fig. 3: Multiple daughter cysts within the primary cyst extending to
the posterior part of the eyeball
Fig. 4: Histopathology of the encised sample confirmed the
diagnosis of hydatid cyst
Brajendra Baser et al
of cases compared with 98% positivity in hepatic hydatosis.
Casoni’s test was found to be negative in our case and it is
now widely accepted that none of the currently employed
serologic tests can rule out the existence of a solitary orbital
The only definite treatment of hydatid cyst is surgical
removal. The size of the cyst, its anatomic location, its
extension into the cranial cavity, the patient’s general
medical condition, the extent of the disease and the surgeon’s
familiarity with each surgical approach decide the most
suitable approach. Meticulous microsurgical dissection,
continuous irrigation, during dissection and adequate
visualization are important for the success. Postoperative
adjuvant chemotherapy with albendazole is always
recommended.9 Rupture and spillage of the contents of the
cysts leads to secondary dissemination with local recurrence,
so postoperative treatment is of great importance.
Mebendazole and albendazole have been shown to be
effective in such cases.3
The outcome of these procedures has been reported
excellent in the vast majority of cases; however, in late stage
cases with extensive optic atrophy and global compression,
enucleation of the globe has been reported.1
The early diagnosis of orbital hydatidosis and its prompt
surgical management has excellent results in the vast
majority of these patients. This makes the importance of its
appropriate diagnosis even more crucial. The clinician
should always include the diagnosis of hydatid cyst in the
differential diagnosis list of orbital mass, especially in
children. Increases of world tourism and migration should
make the clinician to include this quite rare diagnosis in his
list even in nonendemic areas.
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hydatid cyst. Indian J Ophthalmol 2000;48:142-43.