AJTCCM VOL. 28 NO. 3 2022 115
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Background. Hydatid disease is a zoonosis caused by larval stages of cestodes belonging to the genus Echinococcus. e rib location is
exceptional. It presents a real diagnostic and therapeutic challenge.
Objective. To describe the clinical, serological and radiological features and surgical management of rib hydatidosis.
Methods. is is a retrospective study conducted over 4 years, on ve cases of rib hydatidosis. We analysed the clinical and radiological
presentations and the adopted therapeutic procedure.
Results. e average age of our patients was 44 years, without gender predominance. e clinical signs were dominated by the presence
of an immobile swelling of uid consistency without inammatory sign, accompanied by moderate and intermittent localised pain. e
laboratory assessment was nonspecic. e radiological assessment, including chest X-ray and thoracic computed tomography, with and
without contrast, was essential in order to assess the extent of the lesion. oracic magnetic resonance imaging was requested in one case
because of suspicions of a spinal extension. All of our patients underwent a rib excision accompanied by medical treatment of albendazole
24 hours aer the surgery. e follow-up ranged from 1 year to 4 years and did not show any recurrence.
Conclusion. Hydatidosis of the ribs is an exceptional location of hydatid disease. e diagnosis was based on radiology and intraoperative
exploration. e treatment remained essentially surgical by rib excision with anthelmintic drugs to prevent recurrence.
Keywords. hydatid disease, genus Echinococcus, retrospective study.
Afr J Thoracic Crit Care Med 2022;28(3):115-118. https://doi.org/10.7196/AJTCCM.2022.v28i3.193
Hydatid disease is a zoonosis resulting from the growth of the larval
form of Echinococcus granulosus (family Taeniidae).[1] Involvement of
the bones is rare, and the rib location is exceptional even in endemic
countries like Morocco. It poses diagnostic and therapeutic challenges
because of the clinical latency of hydatid disease and the severity of
its prognosis linked to the risk of local recurrence and medullary
compression, in the forms extended to the spine. e aim of our study
was to present the clinical and radiological presentation and specify
the surgical singularity in hydatid disease of the ribs.
Methods
is was a retrospective study conducted between 2016 and 2020,
involving ve patients operated on for rib hydatidosis. Cases with
incomplete medical les were excluded from the study.
Dierent variables were taken into account: age, sex, geographic
area, anatomical localisation of the cyst, dimensions, symptoms, signs,
laboratory tests, imaging, and the surgical approach.
Results
The average age of our patients was 44 years, without gender
predominance; 80% of the patients lived in rural areas. Previous
history: One patient had been operated on for hepatopulmonary
hydatidosis, one patient reported pathological fracture in the aected
rib, and another had been operated on for pulmonary and vertebral
hydatidosis (Table1). e clinical symptoms were insidious in all
cases, characterised by the presence of a swelling of uid consistency
(100% of cases), and moderate intermittent pain, localised (40% of
cases) (Fig.1). e laboratory assessment showed hypereosinophilia
in 40% of cases and negative hydatid serology in all patients. Chest
X-ray was requested rst in 60% of our patients, showing well-dened
rounded opacity associated with osteolysis (Fig.2), and ultrasound
of the so tissues was requested rst in only 40% of cases, showing
hypoechoic multivesicular lesions. oracic computed tomography
(CT), with and without contrast, was requested in 80% of our patients
and conrmed the diagnosis in all cases (Figs 3 and 4). oracic
magnetic resonance imaging (MRI) was requested for one patient for
suspected spinal extension (Fig.5).
Surgical treatment was instituted for all of our patients. The
approach may be just an elective incision or thoracotomy. e choice
of approach depends on the location of the lesion. e surgery consists
of the removal of the cyst with rib excision through healthy areas.
Hydatid disease of the ribs: An exceptional location
S Douni,
1
PhD ; S Sabur,
1
PhD; H T Elmine,
1
PhD; I Marzouki,
1
PhD; M Caidi,
1
PhD; M Bouchikh,
1,2
MB ChB, PhD; A Achir,
1,2
MB ChB, PhD
¹ Department of oracic Surgery, CHU IBN Sina, Rabat, Morocco
2 Faculty of Medicine and Pharmacy, Mohamed V University, Rabat, Morocco
Corresponding author: S Douni (sohail.douni@hotmail.com)
Fig.1. Swelling without inammatory sign localised at the level of the
scar of the PLT.
116 AJTCCM VOL. 28 NO. 3 2022
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We used a scolicidal agent (H2O2) to prevent parasite dissemination.
Pathological examination conrmed the diagnosis by visualising the
hydatid membrane and clarifying its multivesicular character. Aer
24 hours post-surgery, and for 6 months, medical treatment with
albendazole was provided for all the patients. e follow-up for all
patients was uneventful and no recurrence was noted.
Discussion
Hydatid cyst is defined by the development of a larval form of
Echinococcus granulosus transmitted to humans either by direct
contact with dogs or through ingestion of contaminated food. It can
infest several locations in the body, such as the liver, lung or kidney.[1]
Bone location is rare and represents only 0.5 - 2% of all general hydatid
localisations;[2] rib involvement is exceptional and its frequency
is estimated at 0.18 - 1.21%.[3] Hydatid osteopathy is infiltrative,
Table1. Clinical characteristics of patients and treatment
Age Sex Previous history Clinical
Symptoms
delay Location Surgery
Medical
treatment
Follow- up
(mo.)
Case 1 63 F Tumefaction + pain 15 yrs Right 11th
rib
RE Albendazole 26
Case 2 29 F ree episodes of
pathological fracture
of the rib
Tumefaction 8 mo. Le 6th rib PLT + RE Albendazole 48
Case 3 52 M Operated for
hepatopulmonary
hydatidosis
Tumefaction + pain 7 mo. Right 8th
and 9th rib
RE Albendazole 34
Case 4 34 M Tumefaction 6 mo. Right 2nd
rib
PLT Shaw-
Paulson +
RE
Albendazole 36
Case 5 41 M Operated for
pulmonary
hydatidosis
Operated for
vertebral hydatidosis
Tumefaction 4 yrs Right 7th
and 8th rib
RE Albendazole 36
F = female; M = male; RE = rib excision; PLT = posterolateral thoracotomy.
Fig.2. Chest X-ray showing well-limited basithoracic parietal opacity.
Fig.3. oracic CT showing a parietal cystic mass with costal lysis of:
A.the right 8th and 9th ribs; B. the right 2nd rib.
AJTCCM VOL. 28 NO. 3 2022 117
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progressive, with numerous microvesicles and without encystment of
the parasite.[1]
Rib hydatidosis can be primary or secondary owing to spontaneous
rupture of a pulmonary or mediastinal cyst or by puncture of a
subpleural location.[4] Two of our patients had a history of pulmonary
hydatid cyst. e clinical signs of rib hydatidosis are nonspecic;
itis characterised by a slow evolution with moderate intermittent
chest pain at the site of the lesion, while clinical examination reveals
a local tumefaction without inammatory signs, which generally
reects an extension to the so parts of the parasitic lesions, but in
some cases can be asymptomatic.[4-6] e laboratory assessment may
show hypereosinophilia but the rest is unremarkable. e hydatid
serology (total and specic immunoglobulin E (IgE), enzyme-linked
immunosorbent assay (ELISA), Western blot, immunoprecipitation,
indirect haemagglutination test (IHT)) may be positive, but remains
unspecific
[4,5]
In our cases, hydatid serology was performed for all
patients, all of which came back negative, conrming the non-sensitivity
of this examination. e radiological assessment plays a dual role: rst, it
allows the lesion to be located, and second, it provides the opportunity to
nd other locations. e chest X-ray remains the rst-line examination,
as it allows the lesion to be located. Rib hydatidosis manifests as an
opacity of anterior or posterior parietal appearance, parallel to the axis of
the bone without modication of its shape.
[7]
So-tissue ultrasound can
also be requested as a rst step; it will show a hypoechoic multivesicular
image with a posterior shadow.
[4]
ese two examinations, mentioned
above, remain nonspecic.
e thoracic CT, with and without contrast, remains the gold standard
for diagnosis of rib hydatidosis. It highlights multilocular lesions of uid
density with ne partitions, not enhanced aer injection with contrast,
and also makes it possible to show bone lysis and to specify the condition
of the cortex which can be either blown, rolled or broken with endo- or
exothoracic extension. At the level of the so parts, the diusion of the
process gives a characteristic appearance of a cystic mass with a thin
wall or an image of an abscess with a thick wall, or even a pseudotumour
heterogeneous appearance.
[4,5]
A thoracic MRI is requested especially
for costovertebral locations where it is mandatory for preoperative
assessment. It shows images with variable shape, rounded or oval, with
ne walls, low signal on T1-weighted sequences and high signal on
T2-weighted sequences, not taking the contrast except sometimes at
the periphery; though a T1 hypersignal may be observed in relation to
content rich in proteins.
[5,8,9]
In our series, the chest X-ray and the so-
tissue ultrasound were the rst examinations requested but they did not
conrm the diagnosis. e CT, on the other hand, allowed the diagnosis
to be conrmed in 80% of the cases. e MRI was requested in only one
case because of a suspected spinal extension.
The differential diagnosis of rib hydatidosis includes malignant
bone tumours (plasmacytoma or metastases), benign bone tumour
(aneurysmal cysts, neurobromas or giant cell tumours) and osteomyelitis
caused by Mycobacterium tuberculosis or common pathogens.
[4]
e treatment of rib hydatidosis is based rstly on surgery, which
consists of a large rib excision, passing through a healthy area; and
secondly on medical treatment, based on albendazole pre and post
surgery at a dose of 10 or 15 mg/kg (for 6 - 9 months) to minimise the
risk of recurrence.
[4-6,10]
In our series, rib excision through an elective
incision was performed in most cases, but in one case the excision was
partial through a posterolateral thoracotomy (PLT Shaw-Paulson), given
the location of the lesion with placement of a chest tube. All our patients
beneted from albendazole treatment 24 hours aer surgery.
Conclusion
Hydatidosis of the ribs is an exceptional location of hydatid disease.
e diagnosis is based on radiology and intraoperative exploration.
The treatment remains essentially surgical by rib excision and
anthelmintic treatment to prevent recurrence.
Declaration. None.
Acknowledgements. None.
Author contributions. All authors contributed to the study conception
and design. All authors read and approved the nal version.
Funding. e authors received no nancial support for the research,
authorship, and/or publication of this article.
Conicts of interest. None.
Fig.5. T2-weighted MRI image showing a hyperintense cystic lesion with
a hypointense rim located within the right 7th rib.
Fig.4. oracic CT scan with bone reconstruction demonstrating costal
lysis of the right 8th and 9th ribs.
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Accepted 8 July 2022.
