Frequent disease in Tunisia: rare location

ZRIBI Malek |

La tunisie chirurgicale - 2020 ; Vol 2020


Hydatidosis is a parasitic disease known since Hippocrates, is caused by metacestodes (larvae) of Echinococcusgranulosus. It is still a public health problem in endemic countries, especially in Tunisia. Liver and lung are the most common sites of the disease. Primary subcutaneoushydatid cyst  especially in greasy area without any thoracic or abdominal location is extremely rare. We report in this work a case of hydatid cyst in greasy area of the buttocks fortuitously discovered at forensic autopsy made in the forensic department. Through this work, it seems important to us to remember that this diagnosis may not be done in the face of such a location. It can be passed unnoticed. The diagnosis of hydatid cyst should be evoked in front of a  subcutaneousmass even at a greasy area especially in endemic countries. The surgical treatment can be radical. Prevention and screening are the best way to reduce the incidence of this disease.

Mots Clés

hydatidosis, unusual primary hydatid cyst, greasy area, buttocks

Introduction :

Echinococcosis or hydatid disease caused by larvae of the dog's taenia,Echinococcusgranulosus, is an endemic zoonotic  parasitosis. It is a public health problem in many areas of the world including Tunisia. Hydatid disease is widespread throughout the world, especially in areas where hosts, sheep and cattle farming is practiced. Active outbreaks are found mainly in South America, Australia, New Zealand, around the Baltic Sea, the middle east , the countries bordering the Mediterranean Sea and south Africa[1]The most common sites of this disease are liver and lungs. Hydatid cysts can also grow in other organs [2-4]. Primary  subcutaneoushydatid cyst in greasy area is extremely rare. Anyway, very few cases of greasyechinococcosis have been reported worldwide especially in the buttocks .Its incidence stills unknown. We reported a case of hydatid cyst involving buttocks fortuitously discovered at Forensic autopsy made in the forensic department of University hospital of Sfax, Tunisia.



A 62-year-old woman with no known pathological history was admittedin our forensic department in the context of cardiac sudden death.It appeared from the medical history takingthat she was found in breath shortnessin the morning by her daughter. Quickly, she was brought to the emergency where she was declared dead. In the extern examination, a subcutaneous mass in the soft tissue of the buttockmeasuring 5 cm x 3 cm was revealed fortuitously.Furthermore, we didn’t found a similar lesion in her body. At the autopsy, we found signs of necrosis of the myocardium caused by an obstruction of the coronary circulation.  The other organs were  normals. We didn’t found cysts in any organ or site of her body.  So,death was concluded to anatural  bymyocardial infarction. Concerning the mass, it was resected intactly. The cyst was surrounded by greasy tissue (figure 1) . At the opening, it was multivesicular cyst (figure 2).

Histopathological examination of the specimen revealed a pericystic structure, which consisted of connective tissue and scattered hyaline cells showing a necrotic basophilic structure that resembled a cuticular membrane. It was a hydatid cyst, with strictly greasy limits of the specimen


Hydatidosis is a common parasitic disease in North Africa, especially in Tunisia where it is endemic.

The ultimate host is the dog. The intermediate host is the sheep. Human being is accidentally infested and becomes an intermediate host by ingesting a food contaminated by the parasite eggs, or by direct contact with a sick dog[5].

Arrived in the intestines of the man, the parasite infiltrates the portal system to spread in the body. This explains the frequency of hepatic (70% of cases) and pulmonary involvement (10-15% of cases). These two organs constitute also a double physiological filter against the dissemination of the parasite. In consequence, other locations are less frequent[6].

What's interesting in our case is thesolitary and unusual location of hydatid cyst in subcutaneous tissue of the buttocks. On the one hand, because the frequency of the primary subcutaneous hydatid cyst is 2.3% of  hydatid cysts in the  endemic  zone [7]. On the other hand ,it is difficult to explain how the larva can crossboth hepatic and pulmonary filters and constitue asolitary cyst without associated visceral location[8].

There are two mechanisms can explaining a primary subcutaneous location of an hydatid cyst ; direct subcutaneous contamination through an injured skin or subcutaneous colonization of ingested eggs after passing liver and lungs. But, the certatin mechanism stills inclear[9].

The symptomatology is insidious and not very evocative,causing a frequent diagnostic delay.The clinical manifestations come down toa non-inflammatory and painless mass gradually increasing in volume with conservationof the general state[10-13]. However, few cysts are revealed by complications likenerve compressions or infections simulating an abscess or malignant tumor[12, 14, 15].

Serological tests are very often negative. Usually, hydatid serology is only positive in the case of cracked or infected cysts[13].

Standard radiography can highlight intracystic calcification in the case of an aged cyst[16, 17].


Ultrasonography can orientate  the diagnostic. In fact, in typical cases,it allows the diagnosis of hydatidosis by revealing the vesicular membranes, the cystic nature of the mass, its size, its seat and its stage in Gharbi's classification[11, 18].

However,there are atypical forms where the lesion is solidocysticor solid pseudotumoralwhich makes the identification of structures difficult and the establishment of the diagnosis impossible[18].

MRI is the most recommended exam if ultrasonography come insuffisant. It allows us  to establish the diagnosis of soft tissue hydatid cysts including the subcuatneous one. It shows, in addition to the vesicles and membranes, the wall in relative hyposignal in T2 weighted images.Peri-cystic enhancement after injectionof gadolinium, authorizes the diagnosis of soft tissuehydatidosis.MRI also analyse better the locoregional reports[16, 18, 19]. These paraclinicalexaminations are essential forsurgical planning and are useful for follow-up in orderto research possiblelocal relapses.

The treatment of solitary subcutaneous hydatid cyst is surgical. The technique of choice is peri-cytectomy, taking away all the cyst without breaking the wall. The use of fields soaked with hypertonic serum on the operative wound helps to prevent spreading local scolex[11, 16, 18, 20, 21].

Currently, minimal invasive percutaneous treatment options are promising(réfartcileenglish )like puncture,aspiration, injection and reaspiration (PAIR) or drainagepercutaneous injection with no reaspiration[22].

In fact, there have been a number of studies that suggest that PAIR with chemotherapy is more effective than surgery in terms of disease recurrence, and morbidity and mortality[23].

 However, the interest of chemotherapy with albendazole or mebendazole in the solitary locations of the musculoskeletal system remains controversial because of their  difficult dissemination in the cyst fluid[20,21].

Identifying a subcutaneous hydatid cyst can alert the clinician for disseminated hydatid cysts in the body. If a subcutaneous hydatid cyst was primary and treated by total surgical excision, the prognosis is generally good.



Primary hydatid location in the subcutaneous tissue especially in greasy area is exceptional. The symptomatology is often insidious. In fact,  it should be a differential diagnosis of soft tissue masses particularly for patients who lived in endemic regions. This unusual primary location of hydatid cyst is generally considerated like a benign disease. Complete excision is the best treatment option.However,  the best way to fight against hydatid disease, whatever its location, remains the prevention


No conflict of interest


figure1 : the autopsial specimen : the cyst was  resected intact surrounded by greasy tissue

figure2 : cyst multivesicular


Malek ZRIBI: author

Narjes KARRAY: co-author

Aymen TRIGUI:   co-author

Wiem BENAMAR: co-author

Foued FRIKHA: co-author

Samir MAATOUG: conceived study






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figure1 : the autopsial specimen : the cyst was  resected intact surrounded by greasy tissue


figure2 : cyst multivesicular