Isolated brachioradialis symptomatic cysticercosis in a young female: A rare entity surgically managed

Abstract

Taenia solium is a parasite and is endemic in the developing countries due to various unhygienic faecal practices. The disseminated form is commoner with the brain being the most common site of affliction. This report is of a young female patient with complaints of an insidious and progressive swelling of the right forearm. Clinicoradiological features were suggestive of an isolated myocysticercosis which was symptomatic with restricted pronation and supination. The symptoms persisted post a course of Albendazole, and the cyst had to be excised as it was impinging on the median and radial nerves. The patient has been asymptomatic after a 3-month post-operative period with no signs or imaging evidence of residual disease. The presence of isolated intramuscular cysticercosis is an extremely rare and a high index of suspicion is needed for early diagnosis. Although medical management is extremely effective, surgical excision may be required in certain cases.

Introduction

Taenia solium is a parasitic zoonotic disease with man as the definite host. It affects about 50 million individuals worldwide.^1,2 The disease carries a significant burden and impact on Quality of life and Disability adjusted life years (DALY) causing up to 30% cases of epilepsy in endemic areas.³ The disseminated form of the disease is common; however, isolated intramuscular involvement is rare. The management of isolated intramuscular cysticercosis is predominantly medical.⁴ Here, we present a case of a young female patient with isolated intramuscular symptomatic cysticercosis, which required surgical management.

Case report

A 30-year-old female patient developed swelling of the right forearm – which was insidious and progressive. The swelling subsequently caused restricted movement of the right forearm. There was no preceding history of trauma.

Clinical evaluation revealed a 5 cm × 4 cm non-fluctuant, cystic swelling of the right forearm with no induration/tenderness/local rise of temperature. Slip sign and buttonhole sign were negative. The supination and pronation were significantly restricted.

Ultrasonography (USG) revealed a well-defined cystic lesion with a worm-like inclusion and areas of calcification. The cyst was impinging on the median and radial nerves [Fig. 1]. Based on the USG findings, the patient was started on Albendazole for 15 days. However, the movement restriction and swelling persisted after medical therapy with clinical features suggestive of median and radial nerve compression.

Fig. 1.

Ultrasonography (USG) image showing worm-like inclusion in a sac like structure within the muscle.

Subsequently, the patient was transferred to our Centre where an MRI whole body was done which revealed only a right forearm cyst with a T1 hyperintense and T2 hypointense wall with mucosal oedema and intracystic fluid collection [Fig. 2]. The taenia solium serum antibody IgG was positive. No similar lesions were detected elsewhere.

Fig. 2.

Magnetic resonance Image of a Cyst with fluid.

The cyst was subsequently excised into and the patient followed up for 2 months; there is no restriction of the movement, and the imaging is also negative for residue or recurrence.

Histopathological examination of the excised specimen was carried out. Macroscopically, multiple greyish-white soft tissue bits were identified. On microscopy, a host inflammatory reaction around serpiginous central slit-like clear space was seen. The inflammatory response revealed palisading foreign body granulomatous reaction with inner eosinophilic necrotic debris. However, no evidence of cysticercus larva or hooklet was noted [Fig. 3]. Most of the tissue bits showed granulation tissue with dense mixed inflammatory cells comprising of lymphoplasmacytic cells and eosinophils, which were also infiltrating surrounding fibroadipose as well as skeletal muscles. Ziehl–Neelsen stain/Periodic Acid Schiff stain did not reveal any other organisms. Informed consent of patient was obtained for use of images and data for publication purpose.

Fig. 3.

Host fibrous wall with pallisading multinucleate giant cell reaction surrounding collapsed cystic space (scanner view, Hand E).

Discussion

Taenia solium is a parasite for whom man is the definite host and pigs form the intermediate host. The parasite spreads due to unsanitary faecal practices. The pigs consume food contaminated by human faeces. Consumption of uncooked pork leads to the disease in humans or it may simply promulgate via faeco-oral route.⁵

The infective larval form is known as Cysticercus cellulosae, which enter the bloodstream after being broken down in the stomach and gain access to distant sites. When the parasite causes mild GI disturbance, the disease is referred to as taeniasis while spread of the parasite to highly vascular sites such as brain, eyes, muscles, and subcutaneous tissues is addressed as cysticercosis. Neurocysticercosis is the most common form of the disease worldwide.⁶

The disease is endemic in regions of Africa, Eastern Europe, Mexico, and Indian subcontinent. The isolated intramuscular form of the disease is uncommon and presents a diagnostic dilemma.⁷ The swelling lacks specific findings, and usually, radiology is helpful in clinching the diagnosis.

The intramuscular cysticercosis characteristically presents as myalgic type, mass-like, pseudotumor or abscess-like and rarely as pseudohypertrophic type. In our case based on the USG and intra-operative findings, the abscess-like morphology was seen.⁸

USG is an ideal first-line investigation being cheap, non-invasive and detects the worm in cyst. There are about four configurations of sonography described in literature; however, the findings of an oval or round well-defined cystic lesion with an eccentric echogenic scolex are characteristically seen.⁹

MRI is the gold standard. It can help us define the stage of infection and even rule out disseminated disease. The cyst wall is characteristically T1 hypointense and T2 hyperintense with an oval or round shape directed along the course of muscle fibres (4).

Fine needle aspiration cytology with or without rapid on-site evaluation is also considered as a cheap, easy, readily available and reliable tool for identifying the presence of larval parts/inflammation at the site of the lesion, provided it is approachable and amenable to the intervention. However, in our case, the radiological finding was highly suggestive of a worm, and further fine needle aspiration cytology was avoided.¹⁰

Enzyme-linked immunotransfer blot is the most effective immunological modality to detect anticysticercal antibodies in serum with a specificity of 100% and sensitivity of 60–85% for a single cyst lesion.¹¹

The management of the entity is either medical or surgical. Medical management is based on 2 weeks of 10–15 mg/kg/day of albendazole or 3 weeks of 50 mg/kg/day Praziquantel.⁶

Our case was managed surgically due to persistent symptoms even despite medical therapy and the affliction of the median nerve. The MRI and histopathology did not reveal a larva but had highly suggestive features of intramuscular cysticercosis, likely due to the medical therapy started before investigations and excision.¹²The isolated intramuscular lesion is a rare entity and hardly requires surgical management.

Conclusion

The isolated form of intramuscular cysticercosis is a rare entity and lacks definite clinical features. However, a high index of suspicion and directed imaging form the cornerstone of diagnosis. The medical management is effective. Surgical excision was undertaken in this case because of the persistence of the swelling, movement restriction and features suggestive of nerve compression.

Patients/ Guardians/ Participants consent

Patients informed consent was obtained.

Ethical clearance

Not Applicable.

Source of support

Nil.

Disclosure of competing interest

The authors have none to declare.