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 Table of Contents  
Year : 2021  |  Volume : 11  |  Issue : 1  |  Page : 56-59  

Primary pelvic echinococcosis though uncommon but not rare

1 Department of Microbiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
2 Department of Orthopedic, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
3 Department of Pathology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Date of Submission01-Oct-2019
Date of Decision27-Jan-2020
Date of Acceptance01-Feb-2020
Date of Web Publication14-May-2021

Correspondence Address:
Vibhor Tak
Department of Microbiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/tp.TP_64_19

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Echinococcosis is caused by larva of Echinococcus granulosus. Liver being most commonly involved, other organs/body parts such as bone involvement is not so uncommon, especially in cattle-raising countries such as India. Primary osseous echinococcosis remains undiagnosed until complications have developed. We report a case of complicated pelvic echinococcosis presented with left gluteal mass, acetabulum and femoral head destruction, and reduced hip mobility. Pre- and postoperative chemotherapy with albendazole and en bloc surgical removal of the cyst were advocated as the preferred option of treatment. Primary osseous echinococcosis must be kept in mind when encountering a case of chronic bony mass not responding to antitubercular therapy, and hydatid serology should be performed along with other imaging and histopathological examinations to support or confirm the diagnosis to prevent long-term complications.

Keywords: Echinococcus granulosus, gluteal mass, hydatid serology, pelvic echinococcosis

How to cite this article:
Abhishek KS, Shrimali T, Tak V, Nag VL, Banerjee S, Khera S. Primary pelvic echinococcosis though uncommon but not rare. Trop Parasitol 2021;11:56-9

How to cite this URL:
Abhishek KS, Shrimali T, Tak V, Nag VL, Banerjee S, Khera S. Primary pelvic echinococcosis though uncommon but not rare. Trop Parasitol [serial online] 2021 [cited 2023 Feb 4];11:56-9. Available from: https://www.tropicalparasitology.org/text.asp?2021/11/1/56/315934

   Introduction Top

Echinococcosis, also known as “hydatid disease,” is a zoonotic infection caused by the larval stage of Echinococcus. The most common species associated is Echinococcus granulosus, also known as dog tapeworm. With the advancement of phylogenetics, nine species of genus Echinococcus have been recognized so far, namely Echinococcus granulosus, Echinococcus equinus, Echinococcus ortleppi, Elodea canadensis, Echinococcus multilocularis, Echinococcus vogeli, Echinococcus oligarthrus, Echinococcus felidis, and Echinococcus shiquicus.[1] In humans, different species are associated with different diseases. E. granulosus, E. equinus, E. ortleppi, and E. canadensis are known to cause cystic echinococcosis. E. multilocularis is associated with alveolar echinococcosis, whereas polycystic echinococcosis is caused by E. vogeli and E. oligarthrus. No human infection with E. shiquicus has been documented till date.

Echinococcosis is considered endemic in Peru, Chile, Argentina, Uruguay, Southern Brazil, Mediterranean region, East Africa, and Central Asia including China and India. Most of the diseases are caused by Echinococcus canadensis and are usually associated with sheep and cattle as an intermediate host.[2] India being a cattle-farming country, a number of cases of hydatid disease are being reported from different parts of the country including Rajasthan. Although the most commonly affected organ is liver, followed by lungs, uncommon location such as bones, particularly pelvis, is not so rare in this part of the country.

The parasites complete their life cycle in two different hosts. The definitive hosts are usually carnivores (canine, felid, or hyenid), whereas intermediate hosts are usually herbivores (sheep, goats, cattle, camels, and cervids). Humans are unlikely to transmit the disease, and thus they are considered accidental or aberrant hosts. The definitive hosts get infected by worm when feeding on these herbivores, and each worm produces numerous eggs. These eggs are passed in the stool which are infective to the intermediate hosts and can remain infective for months to years and can even survive in freezing conditions while they are sensitive to heat and desiccation.[3] Upon ingestion by intermediate host, the hexacanth embryos are hatched out, which penetrate the intestinal mucosa, enter the circulation, and are carried to various internal organs such as liver, lungs, kidney, spleen, bone, and brain, leading to the formation of cysts, which is composed of host-derived pericyst and endocyst of larval origin. The endocysts have outer acellular layer and an inner germinal layer which gives rise to brood capsules and protoscolices.[4] The cysts are filled with fluid known as hydatid fluid and freely floating abundant hooklets known as hydatid sand.

Hydatid disease is usually asymptomatic and is discovered incidentally during the imaging studies done for some other reasons. The disease becomes symptomatic when it gets rupture leading to anaphylaxis and fistula formation or by mass effect leading to compression of neighboring structures. Primary pelvic echinococcosis, though uncommon, is not so rare with an incidence between 0.2% and 2%.[5] We present a case of primary pelvic echinococcosis with chronic gluteal mass.

   Case Report Top

A 62-year-old male patient, farmer by occupation, presented to the orthopedic outpatient department with the complaint of painful gluteal mass with restricted hip movement for the past 12 years. He had undergone incision and drainage on couple of occasions at a local health-care center. On both of those occasions after a brief period of symptomatic relief, painful swelling reoccurred. On physical examination, a large cystic swelling associated with pain and reduced hip movement was observed over the left gluteal region. With the suspicion of osteoarticular tuberculosis, he had undergone antitubercular therapy without any symptomatic relief from the local hospital. Thus, osteoarticular tuberculosis was kept much lower as a differential diagnosis in this case.

Plain radiograph revealed reduced joint space and cystic lesion with destruction of ischial tuberosity, acetabulum, and femoral head [Figure 1]. Other routine investigations revealed elevated erythrocyte sedimentation rate, C-reactive protein, and eosinophilia with absolute eosinophil count of 730/ml. Renal and liver function tests were found to be under normal range.
Figure 1: X-ray pelvis showing reduced joint space with destruction of ischial tuberosity, acetabulum, and femoral head (arrowhead)

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Serum sample was received by the department of microbiology for hydatid serology to rule out possible parasitic infection. Hydatid serology using immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) (RIDASCREEN Echinococcus IgG, R-Biopharm AG, Germany) was performed following the manufacturer's instruction, and surprisingly, the optical density value was above the cutoff. Hydatid serology result was further correlated with computer tomography scan (CT-scan) and magnetic resonance imaging (MRI) of the pelvis. CT-scan and MRI revealed a multiloculated cyst with destruction of left ischial tuberosity, acetabulum, and femoral head. Few calcified foci were also noted supporting positive hydatid serology.

Based on the above serological and radiological findings, a provisional diagnosis of primary pelvic hydatidosis was made. Surgery was planned and the patient underwent preoperative albendazole chemotherapy, followed by en bloc mass excision of the cyst without rupturing the cyst wall. The removed tissue with a cyst was sent to the department of pathology for histopathological analysis. Hematoxylin and eosin staining revealed a thick cyst wall with few daughter cysts, occasional calcified foci with intense inflammatory responses, and exuberant giant cell reaction against lamellated membranes [Figure 2] and [Figure 3] consistent with hydatid cyst. Postoperative period was uneventful and was subsequently discharged with advice of albendazole (10 mg/kg) chemotherapy for 3 months with a regular follow-up. During his last follow-up, the patient had no fresh complaints. He had better hip movement without pain and was walking with support.
Figure 2: Hematoxylin and eosin staining (×10 objective): intense inflammatory response and giant cell reaction against lamellated membranes (arrowhead)

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Figure 3: Hematoxylin and eosin staining (×40 objectives): Giant cell reaction against lamellated membranes (arrowhead)

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   Discussion Top

Majority of the species of Echinococcus are associated with human infection in one or other forms, of which cystic echinococcosis associated with E. granulosus is the most common. Human cystic echinococcosis is a common zoonosis in rural areas of livestock-raising countries such as India. Andhra Pradesh and Tamil Nadu are having the highest prevalence than the rest of the country.[6] While some authors have reported male predilection,[7] the prevalence of the disease increases with age and affects women more frequently than men.[8]

The liver is the most common organ to be involved in such cases, followed by lungs, kidney, spleen, and muscles. Heart, brain, and bones are extremely uncommon sites.[9] Osseous echinococcosis is not so rare, especially in cattle-raising areas such as Rajasthan. Among osseous echinococcosis, vertebral involvement is the most common, whereas the pelvis is an uncommon site.[10] Primary osseous echinococcosis may remain undiagnosed for long until complication develops.

The differential diagnosis includes infective causes such as tuberculosis and chronic osteomyelitis and noninfective causes such as aneurysmal cysts, osteoclastoma, chondrosarcoma, osteosarcoma, and malignancy.[11]

The diagnosis of osseous echinococcosis mainly relies on imaging techniques; however, serology may be useful to support or even confirm the diagnosis. Serological methods include ELISA, indirect hemagglutination antibody tests, latex agglutination tests, immunofluorescence antibody tests, and immunoelectrophoresis, with ELISA being the most common and simplest of all. Although significant cross-reactivity is seen with other parasitic conditions such as cysticercosis, fascioliasis, and filariasis, still hydatid serology is an important and simple technique to support or confirm diagnosis.

The management of osseous hydatidosis is similar to malignant neoplasm, and surgery remains the gold standard. It involves a combination of pre- and postoperative chemotherapy (albendazole) along with surgical resection. An en bloc excision of the lesion with wide resection of the involved portion of the bone is the procedure of choice for satisfactory outcome.[12],[13] On the other hand, although conservative procedures in the form of aspiration and injection of scolicidal agents are safe and technically simple, they are useful in the management of uncomplicated disease. However, their major disadvantages are chances of cyst rupture leading to anaphylaxis and recurrence.

   Conclusion Top

Pelvic echinococcosis, though uncommon, is not so rare in cattle-raising country such as India. Osseous echinococcosis is associated with severe bony long-term complications. Until the complications start to appear, it may remain undiagnosed for long. Imaging techniques are the most reliable mode of diagnosis, though hydatid serology is an important tool to support or even confirm diagnosis. ELISA is the most common and simple serological tool for early diagnosis or to support other investigational results. Earlier the diagnosis, lesser will be the complications; thus the importance of hydatid serology in diagnosis cannot be ignored, though its sensitivity and specificity are questionable. Surgery in combination with albendazole chemotherapy is the treatment of choice; still, prevention is the best way to reduce the occurrence of this disease.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Nakao M, Lavikainen A, Yanagida T, Ito A. Phylogenetic systematics of the genus Echinococcus (Cestoda: Taeniidae). Int J Parasitol 2013;43:1017-29.  Back to cited text no. 1
Alvarez Rojas CA, Romig T, Lightowlers MW. Echinococcus granulosus sensu lato genotypes infecting humans-review of current knowledge. Int J Parasitol 2014;44:9-18.  Back to cited text no. 2
Eckert J, Gemmell MA, Meslin F-X, Pawłowski ZS, editors. WHO/OIE Manual on Echinococcosis in Humans and Animals: A Public Health Problem of Global Concern. Paris, France, Geneva, Switzerland: World Organization for Animal Health (Office International des Epizooties), World Health Organization; 2001.  Back to cited text no. 3
Díaz A, Casaravilla C, Allen JE, Sim RB, Ferreira AM. Understanding the laminated layer of larval Echinococcus II: Immunology. Trends Parasitol 2011;27:264-73.  Back to cited text no. 4
Ait Benkaddour Y, Mansouri MZ, Rabbani K, Jalal H, Aboulfalh A, Abbassi H. Primary pelvic hydatid cyst an unusual cause of cystic adnexal image (mass). Afr J Reprod Health 2011;15:165-8.  Back to cited text no. 5
Amir-Jahed AK, Fardin R, Farzad A, Bakshandeh K. Clinical echinococcosis. Ann Surg 1975;182:541-6.  Back to cited text no. 6
Palanivelu C, Jani K, Malladi V, Senthilkumar R, Rajan PS, Sendhilkumar K, et al. Laparoscopic management of hepatic hydatid disease. JSLS 2006;10:56-62.  Back to cited text no. 7
Craig PS, Li T, Qiu J, Zhen R, Wang Q, Giraudoux P, et al. Echinococcosis and Tibetan communities. Emerg Infect Dis 2008;14:1674-5.  Back to cited text no. 8
Ammann RW, Eckert J. Cestodes. Echinococcus. Gastroenterol Clin North Am 1996;25:655-89.  Back to cited text no. 9
Zlitni M, Ezzaouia K, Lebib H, Karray M, Kooli M, Mestiri M. Hydatid cyst of bone: Diagnosis and treatment. World J Surg 2001;25:75-82.  Back to cited text no. 10
Song XH, Ding LW, Wen H. Bone hydatid disease. Postgrad Med J 2007;83:536-42.  Back to cited text no. 11
Bhatnagar N, Kishan H, Sura S, Lingaiah P, Jaikumar K. Pelvic hydatid disease: A case report and review of literature. J Orthop Case Rep 2017;7:25-8.  Back to cited text no. 12
Zlitni M, Ezzaouia K, Lebib H, Karray M, Kooli M, Mestiri M. Hydatid cyst of bone: Diagnosis and treatment. World J Surg 2001;25:75-82.  Back to cited text no. 13


  [Figure 1], [Figure 2], [Figure 3]


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