Solitary Cysticercosis Of Deltoid Muscle In A Child: The Diagnostic Dilemma And Case Report

Sujit Kumar Tripathy, Ramesh Kumar Sen, Pebam Sudes, Sarvdeep Dhatt

Abstract:

Isolated solitary intramuscular cysticercosis without involvement of central nervous system is a rare entity. We present a case of solitary cysticercosis of deltoid muscle in a 14 year old vegeterian child who presented with features of focal myositis without any systemic or neurological manifestation.

J.Orthopaedics 2009;6(2)e11

Keywords:

Cysticercosis; Intramuscular cysticercosis; Deltoid muscle; Magnetic resonance imaging

Introduction:

Cysticercosis is no longer an endemic disease of the developing countries only. It is a ‘global problem’, because of the influx of immigrants from endemic areas^1,2. The encysted tape warm larva can lodge in subcutaneous tissues, muscles, eyes, nervous system and many other organs of human body leading to variable presentation. Most soft tissue and muscular cysticercal affection is associated with central nervous system involvement or multiple cysts^1-7. Solitary cysticercosis of muscle without involvement of central nervous system is a rare entity and there are few sporadic handfuls of case reports in the literature^2,3,5,6,8-11. It causes diagnostic dilemma as there is lack of specific features.  We present a case of solitary intramuscular cysticercosis in a 14 year vegetarian child involving the right deltoid muscle, where the diagnosis was established by magnetic resonance imaging.    

Case Report:

A fourteen year male child presented to us with pain and swelling over the lateral aspect of proximal right arm. He had history of trauma over the site by one of his friend with wooden scale in his classroom one day back. . The swelling was soft, diffuse, erythematous and mild tender. There was mild increase in temperature of the local part. The child was advised local and systemic anti-inflammatory medication for the same. Even after 3 weeks of trauma, the swelling did not show any sign of resolution. Radiograph of the local part revealed soft tissue swelling with out any bony injury (Fig 1).  The parents were consolated that it may take another few weeks for resolution considering the entity as post traumatic muscle contusion. The patient came back to us with similar complaint even after 6 weeks. Ultrasound of the right arm showed an intramuscular hypoechoic area of size 1.6 x 0.7x 0.5 cms involving the superior part of right deltoid muscle. The radiologist gave the possible diagnosis of liquefied hematoma or an inflammatory lesion. It is not uncommon to find tubercular pyomyositis or a cold abscess with such presentation particularly in India. Considering the above history and sonography findings cold abscess of right deltoid was suspected. Hematological parameters showed normal complete blood count. But the eosinophil count (eosinophil 16) was raised. With absence of contact history, systemic signs or symptoms, normal chest radiography and most importantly negative tuberculin test; tuberculosis was excluded.  However MRI of the local part was advised before proceeding for aspiration cytology. Right deltoid muscle showed small oval cystic foci of T2 hyperintensity and T1 hypointensity measuring 6x5 mm in size (Fig 2). It was found to be oriented along the direction of deltoid muscle fibers (Fig 3a). A sorrounding area of illdefined, T2 hyperintensity measuring 2.6X 2.4 cm was seen suggestive of edema or inflammatory changes. The central hyperintense foci shows peripheral contrast enhancement in post contrast images. Perilesional contrast enhancement was also seen (Fig 3b). Intermuscular fascia also showed evidence of hyperintensity and enhancement. Adjacent subcutaneous fat was normal. Ipsilateral humerus showed normal cortical and marrow substances. The image finding reliably established it to be intramuscular cysticercosis. The child had no history of seizures or neurological abnormalities and no neurological or systemic abnormalities were elicited on physical and radiological examination.  Patient was put on oral antihelmithic drug albendazole (15mg/kg) for 4 weeks. Along with that NSAID was advised for few days. After completion of the treatment, the swelling had completely subsided without any residual complication.

Fig 1. X-ray of right arm AP view shows the soft tissue swelling, no bony or intraarticular pathology appreciable

Fig 2. MRI of right arm with shoulder joint shows a small cystic focus in the right deltoid muscle (T2 hyperintensity), perilesional T2 hyperintense image suggest the edema or inflammatory changes

Fig 3a and b. Coronal and transverse cut section of MRI show peripheral contrast enhancement in post contrast images around the central hyperintense focus. Perilesional contrast enhancement is also seen. Intermuscular fascia also shows evidence of hyperintensity and enhancement. Adjacent subcutaneous fat is normal. Note should be made that the orientation of the cystic lesion is along the direction of muscle fibre

Discussion :

Cysticercosis occurs when a person ingests pork tapeworm eggs (not the larvae), usually by consumption of raw or undercooked pork, fecally contaminated water, or vegetables. The eggs hatch in the intestine and develop into larvae that penetrate the intestinal wall and invade various organs and tissues of the body. Human cysticercosis is caused by this encysted larva of the tapeworm Taenia solium. It can lodge anywhere in the human body but subcutaneous tissues, muscles, eyes and nervous system are more commonly affected^1,2,4,5,7,10. Children are commonly affected because of increased chances of fomite infection⁵.

Cysticercosis is common in Mexico, Central and South America, Africa, India, China, Eastern Europe, and Indonesia. Infection is very rare in travelers but not uncommon in immigrants from Solitary muscular and soft tissue cysticercal involvement is a rare disease per se and it has been used as a marker of neurocysticercosis. Therefore, central nervous system or ocular involvement should be ruled out if systemic involvement is suspected^1-7.   The intramuscular cyst may remain asymptomatic for a long time and finally disappear quietly; rarely do they calcify. In very rare situation as in the present one; they become inflamed and manifest as a growing area of redness, edema and pain. Inflammation of the tissue suggests death or degeneration of the parasite with leakage of the antigens and cellular response of the body^4,7. In this case the cyst wall might have ruptured because of trauma and the antigens inside the wall have leaked into the surrounding area inciting an inflammatory reaction. Three types of clinical manifestations of muscular cysticercosis have been described: the myalgic, myopathic type; the nodular or masslike type⁴. Our patient had the mass like type presentation, which simulate benign neoplastic conditions of muscles or an intramuscular abscess.

As per the literature laboratory studies in the form of complete blood count and liver function test may not contribute in diagnosis; as they are nonspecific. The WBC count is usually with in normal range and most patients do not have eosinophilia unless the parasitic antigen is leaking into the surrounding tissue and evoke an inflammatory reaction^7,12. The increased eosinophil count in the present case provided adequate hint about helmenthic infection. Because of its atypical presentation, however a diagnosis of cold abscess was made initially. MRI of arm showed it to be a cystic ring enhancement lesion and diagnosis of cysticercosis was made.  

The differential diagnosis of muscular cysticercosis includes lipomas, epidermoid cysts, neuroma, neurofibromas, pseudoganglia, sarcoma, myxoma, pyomyositis or tuberculous lymphadenitis^2,3,5. Plain radiographs rarely show cysticerci except in chronic cases when they calcify. These oval or ellipsoid masses typically lie in the direction of muscle fibres. However, in most cases, high-resolution sonography can facilitate the diagnosis of muscular cysticercosis. Computed tomography and MRI scans are the other modalities used for imaging muscular cysticerci, showing their location, number, and relationship to the surrounding structures^1,2,4,5,7. The diagnosis in the case reported here was first suggested on the basis of MRI findings. MRI can sometime shows charecteristic appearance of solitary cysticercosis and a scolex within. However ultrasound could not contribute in making the diagnosis in this case, as it is highly operator dependent.  MRI clearly showed a cyst with hyperintensity in T2 weighted image. Many authors^8,4,3 had reported that ultrasound and MRI can reliably establish the diagnosis of cysticercosis. Out of the six cases reported by Jhankaria et al³, five had clear cysts that displayed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Four of these cysts had scolices within them. One patient had an ill-defined hyperintense lesion on T2-weighted images without any clear cyst. Similar to their observation, perilesional edema was remarkable in the image findings of present case. On the basis of MRI finding we had started the antihelmenthic treatment (albendazole) and the child responded well. The introduction of praziquantel and albendazole made the treatment of cysticercosis more promising. Multi-center clinical trials found that albendazole is superior to praziquantel. Recent clinical trials have reduced the duration of treatment with albendazole to 8 days¹. However we treated the child as per the old régime with 4 weeks of albendazole therapy. For initial one week we had combined an anti-inflammatory drug for the inflammation to subside. To conclude, cysticercosis should be kept as a differential diagnosis for any focal myositis even with out any neurological abnormalities. 

Reference :

1. Vanijanonta S. Cysticercosis by the Year 2000: an Update. The J tropical med parasit 1999; 22 (1): 34-40

2. Vorachai S, Suphaneewan J. An Intramuscular Cysticercosis, A Case Report with Correlation of Magnetic Resonance Imaging and Histopathology. Chot Mai Het Thang Phaet    2007; 90(6): 1248-1252 

3. Jankharia BG, Chavhan GB, Krishnan P et al. MRI and ultrasound in solitary muscular and soft tissue cysticercosis. Skeletal Radiol 2005; 34: 722–726

4. Asrani A, Morani A. Primary Sonographic Diagnosis of Disseminated Muscular Cysticercosis. J Ultrasound Med 2004; 23:1245-1248

5. Khan RA, Chana RS. A Rare Cause of Solitary Abdominal Wall Lesion. Iran J paediatr 2008; 18(3): 291-292

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7. Gutierrez Y. Cysticercosis, Coenurosis, Sparganosis and Proliferating Cestode Larva. In: Diagnostic pathology of parasitic infections with clinical correlations, 2nd ed. Oxford University Press US 2000. p. 636-638

8. Mani NB, Kalra N, Jain M et al. Sonographic diagnosis of a solitary intramuscular cysticercal cyst. J Clin Ultrasound 2001; 29: 472–475.

9. Bilge EF, Baris T, Ulku K et al. Solitary Cysticercosis in the Intermuscular Area of the Thigh: A Rare and Unusual Pseudotumor with Characteristic Imaging Findings [Case Report: Musculoskeletal Imaging]. Journal of Computer Assisted Tomography 2005; 29(2): 260-263

10. Abdelwahab IF, Klein MJ, Hermann G et al. Solitary cysticercosis of the biceps brachii in a vegetarian: a rare and unusual pseudotumor. Skeletal Radiol 2003; 32: 424-428

11. Brown ST, Brown AE, Flipa DA et al. Extraneural cysticercosis presenting as a tumour in a seronegative patient. Clin inf dis1992; 14:53-558.

12. Falco OB, Pleweig G, Wolf HH et al. Diseases caused by worms. In: Dermatology, Falco OB, Plewig G, Wolff HH, Winkelmann RK Eds. 3rd ed. Berlin, Springer-Verlag; 1984. p. 262-274), Pp:291-292

This is a peer reviewed paper 

Please cite as: Sujit Kumar Tripathy: Solitary Cysticercosis Of Deltoid Muscle In A Child: The Diagnostic Dilemma And Case Report

J.Orthopaedics 2009;6(2)e11

URL: http://www.jortho.org/2009/6/2/e11

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