Sonographic appearance of cysticercosis of the masseter muscle: A case report

Hemant Sawhney; Sanjeev Laller; Anju Anu Jose; Mamta Malik

doi:10.4103/jiaomr.jiaomr_180_18

CASE REPORT

Year : 2019 | Volume : 31 | Issue : 1 | Page : 66-69

Sonographic appearance of cysticercosis of the masseter muscle: A case report

Hemant Sawhney¹, Sanjeev Laller², Anju Anu Jose¹, Mamta Malik²
¹ Department of Oral Medicine, Diagnosis and Radiology, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India
² Department of Oral Medicine, Diagnosis and Radiology, PDM Dental College and Research Institute, Sarai Aurangabad, Bahadurgarh, Haryana, India

Date of Submission	10-Nov-2018
Date of Acceptance	01-Feb-2019
Date of Web Publication	23-Apr-2019

Correspondence Address:
Dr. Hemant Sawhney
Department of Oral Medicine, Diagnosis and Radiology, School of Dental Sciences, Sharda University, Greater Noida - 201 310, Uttar Pradesh
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jiaomr.jiaomr_180_18

Abstract

Cysticercosis is an infection with the larval (cysticercus) stage of Taenia solium. The larvae form cysts commonly in brain, meninges, and eyes, which together constitute 86% of cases with remainder located in the muscles, heart, lungs, and peritoneum. Cases in the maxillofacial region, including tongue and cheek muscles are rare. We report a rare case of cysticercosis involving right masseter muscle presenting as a facial swelling, diagnosed on the basis of fine-needle aspiration cytology and high-resolution ultrasonography and managed conservatively.

Keywords: Cysticercosis, intramuscular, masseter, parasites, ultrasonography

How to cite this article:
Sawhney H, Laller S, Jose AA, Malik M. Sonographic appearance of cysticercosis of the masseter muscle: A case report. J Indian Acad Oral Med Radiol 2019;31:66-9

How to cite this URL:
Sawhney H, Laller S, Jose AA, Malik M. Sonographic appearance of cysticercosis of the masseter muscle: A case report. J Indian Acad Oral Med Radiol [serial online] 2019 [cited 2022 Jun 30];31:66-9. Available from: https://www.jiaomr.in/text.asp?2019/31/1/66/256893

Introduction

Cysticercosis in humans is infection with the larval form (cysticercosis cellulosae) of the pork tapeworm Taenia solium. It is endemic in Southeast Asia, Mexico, Central and South America, and Africa.^[1] Tapeworm infection is common in developing countries where the combination of rural society, crowding, and poor sanitation allows greater opportunities for fecal contamination of food and water.^[2] Central nervous system involvement is the most common presentation in patients with cysticercosis. The location of cysts in order of frequency is the central nervous system, subcutaneous tissue and striated muscle, vitreous humor of the eye, and rarely other tissues. Muscular cysticercal involvement as a solitary lesion is a rare disease. Cysticerci in the muscles generally do not cause symptoms, they present as nodules and can be felt as lumps under the skin, which tend to appear and disappear or they can present as muscular pseudohypertrophy.^[3]

We report a rare case of cysticercosis involving right masseter muscle presenting as a facial swelling associated with pain and reduced mouth opening. In the present case, the correct diagnosis was made on the basis of high-resolution ultrasonography of the masseter muscle, supported with fine-needle aspiration cytology and managed conservatively.

Case Report

A 19-year-old female patient reported with a complaint of swelling, which was insidious in onset on the lower right side of face since 2.5 months. Patient had experienced dull, continuous pain, and limited mouth opening. There was no history of discharge or paresthesia associated with the swelling. Patient gave a history of being medicated for 40 days by varying practitioners following which the swelling used to subside but never resolved completely. The patient was vegetarian by diet. Systemic examination of the patient revealed no other similar swellings or regional lymphadenopathy. On extraoral examination, a solitary diffuse swelling, which slowly increased to the present size of approximately 40 × 60 mm was present on the right lower one-third of face extending from alatragal line to the lower border of mandible and medially 20 mm behind the angle of mouth to 10 mm ahead of posterior border of ramus [Figure 1]. The swelling was firm to hard in consistency, tender, with a local raise in temperature. Intraoral examination revealed erupted third molar without any abnormality.

Figure 1: Clinical photograph of the patient showing a solitary diffuse swelling on the right lower one-third of face (red arrow)

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Blood, urine, and stool examination failed to show active parasitosis. Panoramic radiographic report was inconclusive. Ultrasound-guided fine-needle aspiration cytology yielded a blood tinged aspirate revealing larval fragments identified as lightly stained outer wavy membrane and multiple tiny ovoid nuclei in the fibrillary stroma with chronic inflammatory cells, few degenerated squamous cells, and calcified debris suggestive of parasitic infestation. High resolution sonography was performed using Logiq 500 PRO machine (GE Medical Systems), with a linear probe at 12 MHz frequency. In ultrasonography, there was an ill-defined soft tissue swelling of approximately 41 × 20 × 26.5 mm with an embedded cystic area of approximately 10.6 × 81 × 10 mm and an internal calcific nidus of approximately 2 mm in the right masseter muscle [Figure 2].

Figure 2: Ultrasonogram of the right masseter muscle showing an ill-defined soft tissue swelling with an embedded cystic area and an internal calcific nidus

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The patient was managed conservatively and was prescribed Albendazole 400 mg tablets twice daily for 14 days and Dexamethasone sodium phosphate 8 mg intramuscular injections twice daily for 5 days, followed by 4 mg intramuscular twice daily for 5 days, and then by 4 mg intramuscular once daily for 5 days. After 15 days of conservative treatment, the swelling completely resolved. Patient was followed up for a period of 3 years and no recurrence was reported [Figure 3].

Figure 3: Clinical photograph of the patient on 15 days follow-up showing complete resolution of the swelling

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Discussion

Cysticercosis is caused by the larval form of the pork tapeworm Taenia solium. Ingestion of inadequately cooked infected pork leads to the development of the adult worm in the small bowel of humans who are definitive hosts. The eggs hatch in the small intestine, releasing oncospheres that penetrate the bowel mucosa and enter the bloodstream to reach various tissues, where they develop to form a cysticercus cellulosae, which is the encysted larval form of T Solium. These can remain viable in this stage for as long as 10 years in humans. Living larvae evade immune recognition and do not elicit inflammation. When the larva dies, it induces a vigorous granulomatous inflammatory response that may produce symptoms, depending on the anatomic location.^[4],[5],[6]

In cysticercosis, the clinical manifestations are variable. The organism most often invades the central nervous system, eye, subcutaneous tissue, skeletal muscle and heart, but occasionally the lungs, liver, and kidney may be affected.^[5] Neurological manifestations, known as neurocysticercosis, are most common and may manifest as seizure, hydrocephalus, and signs of raised intracranial tension.^[7] Maxillofacial cysticercosis is rarely seen and is caused by the evolution of the oncospheres that have reached this area by the circulatory route.^[8],[9] The present case had cysticercosis of masseter muscle presenting as a diffuse swelling on the right side of face associated with pain and reduction in mouth opening.

In the muscular form, three distinct types of clinical manifestations have been described: the myalgic type; the masslike, pseudotumor, or abscess like type; and the rare pseudohypertrophic type. During the death of the larva, there is leakage of fluid from the cyst. The resulting acute inflammation may result in local pain and myalgia. Alternatively, degeneration of the cyst may result in intermittent leakage of fluid, eliciting a chronic inflammatory response, with collection of fluid around the cyst, resulting in the mass like, pseudotumor, or abscess like type. Alternatively, the cyst retracts, its capsule thickens, and the scolex calcifies, as seen in our case. Later on, the cyst is completely calcified.^[4],[10] When multiple, they give a “starry night” appearance on computed tomography. These are seen as multiple millet seed-shaped elliptical calcifications in the soft tissues on plain radiography.^[4]

The diagnosis is relatively difficult to make solely on a clinical basis because the manifestations are not specific, with several clinical differentials such as lipomas, epidermoid cysts, neuroma, neurofibromas, pseudoganglia, sarcoma, myxoma, pyomyositis, cold abscess, or tuberculous lymphadenitis. Plain radiographs rarely show cysticerci except in chronic cases when they calcify. However, in most cases, high-resolution ultrasonography 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.^[11] Saran et al. proposed the use of fine-needle aspiration cytology, which identifies the tegument layer of the larva.^[12] Currently, other diagnostic tools include serology, which is helpful in patients with multiple lesions where immunodetection of cysticercosis can be achieved in sera, cerebrospinal fluid, saliva, enzyme-linked immunosorbent assay, or enzyme-linked immunoelectrotransfer blot, but it is important to consider that individuals living in an endemic area may have antibodies because of an exposure instead of established infection.^[13] Histopathological examination confirms the diagnosis of cystiercosis by the detection of cystic space containing the Cysticercosis cellulosae.^[13] The diagnosis in the case reported here was suggested on the basis of ultrasonographic findings and supported by fine needle aspiration cytology.

There are only few cases reported of ultrasonographic features of cysticercosis.^{[4],[5],[10],[14],[15]} On ultrasonography, cysticercosis can appear as the cysticercus cyst with an inflammatory mass around it, as a result of the death of the larva. It can also appear as an irregular cyst with very minimal fluid on one side, indicating the leakage of fluid. The eccentric echogenic protrusion from the wall because of the scolex is not seen within the cyst. This may be because the scolex escapes outside the cyst or because of the partial collapse of the cyst. The third appearance is a large irregular collection of exudative fluid within the muscle, with the typical cysticercus cyst containing the scolex situated eccentrically within the collection. This may be because of chronic intermittent leakage of fluid from the cyst, leading to florid inflammatory exudates. In all three types of appearances, the salient diagnostic feature is that of the cysticercus itself, which appears as an oval or round well-defined cystic lesion with an eccentric echogenic scolex in it, as was seen in the present case. The fourth ultrasonographic appearance is that of calcified cysticercosis. It appears as multiple elliptical calcifications in soft tissue similar to the pathognomonic millet seed-shaped elliptical calcifications in soft tissues. These appearances on high-resolution ultrasonography are pathognomic of cysticercosis and definitive diagnosis can be made with greater confidence.^[4] In our case, ultrasonography revealed cysticercus as an elliptical cyst with echogenic scolex and surrounding inflammation in the masseter muscle.^[4],[10]

Surgical excision is advised for soft tissue cysticercosis with abscess. Cysts without abscess can be managed with antihelminthetics drugs alone.^[16],[17] Medical treatment with praziquantel or albendazole has been recommended for neurocysticercosis and subcutaneous cysticercosis.^[5],[13] The present case was successfully managed conservatively with albendazole and steroids as recommended by Mittal et al.^[10] Preventive measures are important and include the thorough cooking of pork and all vegetables and early detection and complete removal of the worm, including the head.^[5]

Conclusion

The diagnosis of cysticercosis should be considered as differentials in oral solitaire nodular lesions presenting in patients living in an endemic area. High-resolution ultrasonography, being noninvasive and nonionizing, plays an important role in establishing the diagnosis in patients with muscular cysticercosis. This case emphasises on the role of oral medicine specialist in the definitive diagnosis of muscular cysticercosis based on ultrasonographic appearance and its conservative management.

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

Nil.

Conflicts of interest

There are no conflicts of interest.

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