Primary muscular hydatidosis. US, CT and MR findings

Primary Hydatid Cysts in the Extremities: A Systematic Review of the Literature

Primary hydatid cysts (PHCs) in the extremities are uncommon, presenting in the majority of cases with atypical clinical features. Radical surgical excision remains the mainstay of treatment. The aim of our study was to accumulate the already published data on PHCs in the extremities in terms of demographic, diagnostic, and therapeutic aspects. Three electronic databases were meticulously searched for articles published until 2024. A total of 85 studies comprising 118 patients were finally included in our review. Sixteen patients (13.5%) were diagnosed with a hydatid cyst in their upper extremity, 94 (79.7%) with a PHC in the lower extremity, and eight (6.8%) with an echinococcal cyst in the axilla. Pain and swelling were the most frequent symptoms, whereas only two patients were completely asymptomatic. The mean lesion size was 11.6 ± 7.1 cm. Preoperative serology investigation was reported in 82 out of 118 (69.5%) patients; among them, 33 (44.6%) cases had a positive preoperative serology test. The vast majority of patients (96.6%) were treated with an interventional procedure either surgical or radiological, and only seven experienced postoperative complications. No anaphylactic reaction was described perioperatively. Although preoperative diagnosis of PHCs is challenging, they should be considered in the differential diagnosis of soft tissue lesions. Treatment strategies should be individualized on a patient basis, while radical surgical excision remains the gold standard treatment.

Case Report: Infected primary hydatid cyst of the thigh

Hydatic cyst may occur in many organs such as the liver, lung, brain or heart with radiologic features of liver and lung involvement being well known. The musculo-skeletal site is infrequent accounting for 0.7-3% cases of all cases resulting from direct implantation of oncospheres more often than hematic dissemination. We report the case of an 18-year-old female student who visited our hospital because of a swelling in the posteroexternal aspect of the left thigh that had grown during the previous six months and had become tender in the previous month with setup of fever three days before admission. Superficial ultrasound and magnetic resonance imaging demonstrated a cystic mass of the posterior compartment of the thigh developed within the short chief of the biceps femoris. Serology for hydatid cyst was positive. The diagnosis of an infected hydatid cyst was suspected preoperatively, and the patient was given antibiotics and anthelminthic treatment. The cyst was then completely excised and the histopathologic exam confirmed the hydatic origin. The patient was put on oral anti-helminthics and has been on regular follow up for last twelve months with no evidence of recurrence. Hydatidosis rarely occurs in the soft tissues and the diagnosis is challenging particularly when it is secondary infected. Hydatid serology provides certainty in the diagnosis of echinococcosis when it is positive. When it's negative, imaging (Ultrasound, Computed tomography (CT) and Magnetic resonance imaging (MRI)) may be an approach for making the diagnosis revealing the most characteristic features of hydatid cyst.

A rare case of femoral hydatidosis

BACKGROUND

We present a case of a hydatid cyst located in the left thigh.

CASE REPORT

A 67-year-old man was admitted to our department with a 10 × 5 × 4 cm mass in the medial compartment of the left thigh. Computed tomography scan indicated possible hydatidosis. Serological testing (indirect hemagglutination) was positive for hydatidosis. The patient was operated seven years ago for liver hydatidosis.

RESULTS

The patient, after evaluation, underwent surgical excision of the cyst under epidural anesthesia. The cyst was located in the left quadriceps muscle; had a soft, elastic substance; was firmly attached to the muscle fibers; and contained transparent fluid and daughter cysts. Histologic examination confirmed the initial diagnosis. The patient was discharged on the fifth postoperative day.

CONCLUSIONS

The diagnosis of muscular hydatidosis is difficult and the usual diagnostic methods are the serological tests for hydatidosis and imaging (e.g., ultrasound, computed tomography, and magnetic resonance imaging). In every soft tissue mass with benign characteristics the existence of a hydatid cyst should always be considered. Careful surgical excision of the intact cyst is the treatment of choice, but complementary control for liver-or other organ-hydatidosis should be performed.

Kyste hydatique musculaire

PURPOSE OF THE STUDY

Echinococciasis or hydatid disease is a cosmopolite antropozoonosis common to humans and several mammal species. The disease results from the development of the larval or hydatid form of the canine tenia (Echinococcus granulosis) in the organism. Hydatic cysts are uncommonly found in muscles, even in endemic zones. The purpose of this work was to describe the epidemiological, clinical and therapeutic aspects of hydatid cysts observed in muscles based on our clinical experience and data in the literature.

MATERIAL AND METHODS

For this study, we collected data on eleven cases of hydatid cysts in muscles treated surgically at the Sousse University Hospital in Tunisia over a 17-year period from 1985 to 2002. We noted epidemiological, clinical, ultrasonographic and laboratory data which were analyzed to better detail the characteristic features of these localizations.

RESULTS

Mean patient age was 30 years (range 7-50). All patients lived in rural areas where sheep raising and contact with dogs was common. Patients consulted for a tumefaction of the soft tissue which increased in volume progressively. The muscle focus was generally unique and primary. The proximal muscles of the limbs were involved predominantly. Ultrasonography was performed for nine patients and suggested the diagnosis in all cases. The typical feature was a liquid echostructure in an endemic context. Computed tomography was performed in four patients with deep cysts. Magnetic resonance imaging was not used. Surgical treatment was used in all cases with a pericystectomy in six. Early outcome was favorable excepting one case of suppuration of the resection zone observed in one woman. At 2.5 years, there have been no cases of local or distant recurrence.

DISCUSSION

Several factors would explain the exceptional nature of muscle localizations of hydatid cysts: efficacy of the hepatic and pulmonary barriers, muscle environment not favorable for growth of hydatid larvae. The predominant localization in the proximal muscles of the lower limbs could be explained by the volume of the muscle mass and its rich blood supply. It is important to establish the diagnosis preoperatively in order limit the risk of anaphylactic shock or dissemination in the event of puncture or accidental opening of the cyst during resection. Ultrasonography is the diagnostic tool of choice. Surgery is required for treatment, ideally by en bloc total pericystectomy. Medical treatment with imidazoles has little efficacy for the treatment of muscular hydatid disease.

CONCLUSION

Hydatid cysts are rarely found in muscles, even in highly endemic zones. The diagnosis must nevertheless be entertained depending on the clinical and endemic context. Ultrasonography, and accessorily magnetic resonance imaging, are the exploration tools of choice to confirm the diagnosis before surgery and avoid puncture. Exclusively surgical treatment is indicated, ideally for total pericystic resection without rupture.