Skeletal Muscle Echinococcosis: A Rare Manifestation of Echinococcal Disease.

Abstract

Brief ReportsSkeletal Muscle Echinococcosis: A Rare Manifestation of Echinococcal Disease. Mohammed Ghatasheh and MD FRCR Mohammed EtaiwiMD Mohammed Ghatasheh Address reprint requests and correspondence to Dr. M. Ghatasheh: P.O. Box 1947, Amman, 1118 Jordan. From the Department of Radiology, King Hussein Medical Center, Amman, Jordan Search for more papers by this author and Mohammed Etaiwi From the Department of Radiology, King Hussein Medical Center, Amman, Jordan Search for more papers by this author Published Online::1 May 2002https://doi.org/10.5144/0256-4947.2002.245SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionHydatid cyst is a common disease in Jordan. Skeletal muscle involvement with hydatid disease (or echinococcosis) is rare.1–3 We describe the sonographic (US), CT and magnetic resonance (MR) findings in five cases of skeletal muscle hydatid disease which was presented at the Radiology department at King Hussein Medical Center (KHMC) in Amman, Jordan.PATIENTS AND METHODSBetween June 1996 and September 1999, five patients aged between 12 and 35 years (three males and two females) with musculoskeletal hydatid disease, presented to KHMC. Four of the cysts were in the gluteal region and one in the para-vertebral muscles of the neck. The patients were living in the rural areas of Jordan. One of them, a 12-year-old boy, presented with right posterior neck mass of one-year duration. A diagnostic fine-needle aspirate taken was inconclusive. One month later, ultrasound scan showed a well-defined oval cystic mass lesion with a double wall (Figure 1). The diagnosis of hydatid cyst was suspected, and liver ultrasound scan showed a multiloculated hydatid cyst in the right lobe of the liver. Neck MR scan showed oval cystic lesion in the right paravertebral muscle, with low-intensity rim and internal undulating membare (Figure 2).Figure 1. Ultrasound scan of the neck showing an oval cystic mass lesion with double wall and internal membrane in the right paravertebral muscles.Download FigureFigure 2. Sagittal MR image of the neck (TR 690, TE 24 ) showing oval hyperintense cystic lesion in the right paravertebral muscles with lowintensity rim and internal hypointense linear membrane.Download FigureAnother patient, a 20-year-old female, presented with vague abdominal pain. Ultrasound scan showed a large multiloculated hydatid cyst in the left lobe of the liver. CT scan confirmed the ultrasound scan finding. An incidental similar multiloculated hydatid cyst was seen in the left gluteus maximus muscle (Figure 3). Upon questioning, the patient, indicated that she felt a lump in her left gluteal region.Figure 3. CT scan showing multiloculated hydatid cyst in the left gluteus maximus muscle.Download FigureThe other three patients presented with gluteal lumps (two on the right and one on the left side). US and CT scan showed multiloculated cystic lesions in their respective gluteus maximus muscles. Two patients were found to have multiloculated liver hydatid cyst and the third had normal liver scan. All cystic lesions were surgically removed and proved to be hydatid cysts. All patients were found to have normal chest x-rays.DISCUSSIONThe Middle East is endemic for echinococcosis. The larval form of the genus Echinococcus, of which Echinococcus granulosus is the most common cause of the disease. The liver and lungs are the most frequently involved organs.1 Although any organ in the body may be involved, a hydatid cyst in muscles is extremely rare. The mean incidence of echinococcosis in Jordan is 2.9 per 100,000 and is higher in rural areas.1 The liver is the most common organ to be involved (54.5%), followed by the lungs (12.1%).1A case of hydatid cyst of the adductor muscle group causing obstruction of the femoral artery and vein was described in Turkey.4 Another case of hydatidosis in the pectoralis major muscle was described by Abdel-Khaliq.5 Hydatid cyst of rectus and back muscles was described by Pouche et al.2 Hydatid cyst of the gluteal and neck muscles have not been reported.Most patients with muscle hydatid disease will have liver hydatid disease as in the presented cases (80%). Appearance of hydatid cysts in the muscles is similar to hydatid cyst elsewhere in the body. They have thin walls resembling the pericyst, with internal small daughter cysts appear on US scan.3,6,7 (Figure 1). Simple cysts do not demonstrate internal structures, although multiple echogenic foci due to hydatid sand may be seen within the cyst by repositioning the patient (snow-storm sign).8 On CT, hydatid cyst appears as well defined cystic lesion with daughter cysts, and may contain septae or debris (Figure 3). On MR, hydatid cyst has a typical appearance: a thin low-intensity rim likely representing the pericyst, which is rich in collagen and is generated by the host (hypo-intense rim).8 The internal hydatid sand gives heterogeneous high signal intensity on all pulse sequences. However undulating membranes or daughter cysts appear as hypo-intense linear regions within the high-signal intensity hydatid sand on T2W images7 (Figure 2). Lewall classified hydatid cysts into three types according to their imaging appearance.9 Type I is a fluid-filled cyst-like structure, which may proceed to a type II lesion if daughter cysts and/or matrix develop. Type III is mummified, inert calcified lesion. According to this classification, all our cases are type II cysts.In endemic areas like Jordan, any person who presents with a muscle lump must have, among the differential diagnoseis, the possibility of hydatid muscle disease. On the other hand, a patient with liver hydatid disease must be examined for hydatid disease involving other sites of the body.ARTICLE REFERENCES:1. Kamhawi S. "A retrospective study of human cystic echinococcosis in Jordan" . Ann Trop Med Parasitol. 1995; 89:409–14. Google Scholar2. De Cesare V. "Unusual localization of hydatid disease: an 18-year experience" . G Chir. 1994; 15:83–6. Google Scholar3. Lewall DB, Mocorkell SJ. "Hepatic echinococcal cyst: sonographic appearance and classification" . Radiolgy. 1985; 155:773–6. Google Scholar4. Milanese A, Camana GP, Carbone P. "Echinococcus cyst in the pelvic cavity: presentation of case" . Minnerva Urol Nephrol. 1991; 43: 111–4. Google Scholar5. Abdel-Khaliq RA, Othman Y. "Hydatid cyst of pectoralis major muscle: case report" . Acta Chir Scand. 1986; 152:469–71. Google Scholar6. Sabih D, Sabih Z, Khan AN. "“Congealed water lily” sign: a new sonographic sign of liver hydatid cyst" . J Clin Ultrasound. 1996; 24: 297–303. Google Scholar7. Lupetin AR, Dash N. "Intrahepatic rupture of hydatid cyst: MR findings" . Am J Roentgenol. 1988; 151:491–2. Google Scholar8. Pedrosa I, Saiz A, Arrazola J, Ferreiros J. "Hydatid disease: radiologic and pathologic features and complications" . RadioGraphics. 2000; 20: 795–817. Google Scholar9. Lewall DB. "Hydatid disease: biology, pathology, imaging and classification (review)" . Clin Radiol. 1998; 53:863–74. Google Scholar10. Shamsi K, Schepper AD. Medical imaging of focal liver lesion. Elsevier; 1994;42–53. 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