Key-words:
Albendazole - cysticercosis - Taenia solium - temporal pain
Introduction
Cysticercosis involving the central nervous system is well known and most of them
present with seizures. The involvement of skeletal muscles in the region of head and
neck is less commonly reported in the literature.[[1]] These cases are difficult to diagnose because of their rarity and the clinical
features may mimic other maxilofacial pathologies. We here describe a case of isolated
temporalis muscle cysticercosis in a young female, whose symptomatology mimics dental
caries. Good clinical and radiological outcomes are noted after medical management.
The differential diagnosis as well as the importance of radiological investigations
in these rare entities further emphasized.
Case Report
A 28-year-old female presented to the outpatient neurosurgery department for evaluation
of right temporal headache and difficulty in chewing for 3 months. She was diagnosed
to have dental caries of the right second molar tooth at a local hospital and was
initially considered the cause of her symptomatology. She was referred to us as she
did not improve after 2 months of anti-inflammatory and analgesics. On evaluation,
there was mild tenderness in the right temporal region without any identifiable swelling.
However, on palpation, there was induration over the right temporal area. There was
no focal neurological deficit. Magnetic resonance imaging (MRI) was advised with a
differential diagnosis of temporal arteritis. Radiology revealed a bulky right temporal
muscle. There was an elliptical intramuscular enhancing lesion appeared hypointense
on T1, hyperintense on T2 with eccentric hypointense dot and perilesional edema [[Figure 1]]a and [[Figure 1]]b. A radiological diagnosis of temporalis muscle cysticercosis was made. Screening
radiology of the brain was normal. She was advised albendazole 15 mg/kg body weight
with a tapering dose of steroids (dexamethasone). She improved gradually and at 6-month
follow-up, she was symptom free. MRI at the last follow-up showed complete resolution
of the lesion [[Figure 1]]c and [[Figure 1]]d.
Figure 1: (a) T2-weighted magnetic resonance imaging showing bulky right temporalis muscle
with hyperintense lesion and hypointense ring surround it (red arrow). (b) T1-weighted
magnetic resonance imaging showing hypointense right intra temporalis muscle lesion
(yellow arrow). (c and d) Follow-up magnetic resonance imaging at 6 months showing
complete resolution of the lesion
Discussion
Cysticercosis is endemic in Asian countries. Man acts as a definite host for the causative
parasite Taenia solium.[[2]] They spread to distant sites in the body through the bloodstream. Probably because
of the high vascularity, these parasites have a strong predilection for the central
nervous system. Most of the patients present with clinical symptoms of seizure and
headache. In the active phase, they respond well to antihelminthic drugs. At times
when the parasite disseminates, it may affect the heart, lungs, eyes, and skeletal
muscles.[[3]] Very few cases of isolated temporalis muscle cysticercosis have been reported in
the literature. Most often, such patients present with temporal headache with a palpable
swelling, difficulty in chewing, and in acute inflammatory stage, they may also present
with trismus.[[1]] The accurate pathophysiology of isolated temporalis muscle cysticercosis is not
known. Dissemination of the parasite through the bloodstream usually results in distant
site cysticercosis. Theoretically, high flow through the internal carotid artery is
responsible for high incidences of intracranial involvement. Accidental migration
through the external carotid artery (ECA) may result in the deposition of the parasite
at sites supplied by its terminal branches. Temporalis muscle receives extensive blood
supply from the internal maxillary artery which is one of the terminal and large branches
of ECA. This is probably the reason for temporalis muscle cysticercosis, an unusual
extracranial site.
Due to their rarity, isolated skeletal muscle involvements are difficult to diagnose.
Clinically, they mimic any inflammatory pathology involving the maxilofacial region,
as in our case. Cysticercosis may appear as a cystic lesion in the intramuscular plane
with an echogenic nidus on ultrasound.[[3]] On MR imaging, the T2 hyperintense lesion with hypointense focus (scolex) can be
identified. Cysticercosis serology like enzyme-linked imunosorbent assay and enzyme-linked
immunoelectrotransfer blot tests may further establish the diagnosis.[[4]]
These cases usually manage with antihelminthic drugs. Albendazole 15 mg/kg body weight
and praziquantel 50 mg/kg body weight per day in divided doses for 30 days is the
standard treatment.[[3]],[[4]] Before starting drug therapy, screening of the brain should be done to look for
associated neurocysticercosis and ocular cysticercosis where the latter considered
as a contraindication for albendazole. Intramuscular cysticercosis usually responds
well to medical management and may not require surgical interventions.
Conclusion
Isolated cysticercosis of the temporalis muscle, though rare, should be kept as a
differential in patients from endemic areas presenting with unilateral pain and swelling
of the temporal region. Careful evaluation of radiology is essential to establish
the diagnosis. Good clinical and radiological improvement usually seen with drug therapy.
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understand that their names and initials will not be published and due efforts will
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