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Cysticercosis in human is caused by infection with the larval stage of Taenia solium. Muscular infestation is common in developing countries like India, but it rarely involves the head and neck region, and is often seen as a diagnostic dilemma for the clinician. Therefore, parotid cysticercosis is an uncommon entity, a diagnostic challenge especially in endemic regions of Asia, Africa and Latin America . We report a rare case of 64-year-old man presented with a firm nodular swelling in left parotid region that was diagnosed as cysticercosis after all thorough investigations and managed medically..
Cysticercosis is a parasitic disease caused by larvae of Taenia solium also known as pork tapeworm. The etiopathogenesis is due to the ingestion of food, vegetables or water contaminated with T. solium eggs or inadequately cooked pork containing cysticerci . It is a “biological marker” of the social and economic development of a community . Central nervous system, subcutaneous tissue, striated muscle, vitreous humour of eye are the most commonly affected sites. However, involvement of the head and neck region is uncommon for cysticercosis as very few cases have been reported in the parotid region and poses difficulty in clinical diagnosis . Here we are presenting a rare case of parotid swelling where workup revealed it to be cysticercus cellulose.
A 64-year-old relatively healthy male, yoga instructor by profession, moderately built, vegetarian, presented to the out-patient department with a swelling over the left side of face in front of the ear since last 4 days. The swelling was insidious in onset, gradually progressive since last 3 months which had rapidly increased in size in last 4 days associated with mild pain. Patient gave no history of trauma, tobacco chewing, smoking, difficulty chewing or talking, fever, weight loss, discharge from the swelling and no relevant previous family history.
Local examination revealed a single solitary swelling of size 3.5x4 cm, firm in consistency, mobile, spherical in shape, non-fluctuant, non-tender in nature on left side of the face extending horizontally from 1cm below and anterior to the tragus upto the angle of mouth and vertically extending from the zygomatic process superiorly upto the body of mandible inferiorly, mild local rise of temperature over the skin was present. Lymph nodes around the area were not palpable. Mouth opening was adequate with fair oral hygiene. The following differential diagnosis were included: parotid sialadenitis, mumps, parotid abscess, parotitis, tubercular lymphadenitis, tumour (Figure 1).
Routine blood work up was within normal limits. Chest X-ray was normal. High resolution ultrasonography revealed an echoic cystic lesion measuring approximately 10x9mm with internal echoes in left the parotid region. Fine needle aspiration cytology was done and smears prepared, air dried and stained with Giemsa stain, Microscopic examination of the smear revealed mildly hyperplastic salivary acini with ductal cells and thin fibrovascular stroma with no evidence of granulomatous inflammation or malignancy. The patient was given a course of oral cefuroxime
500mg twice daily for 7 days and asked to follow up. There
was no change in the size of swelling after 1 week of antibiotic.
Subsequently a CECT face and neck was ordered which revealed
well defined cystic lesion measuring approximately 11x9mm
noted in the superficial layers of the left masseter muscle deep to
parotid gland. The impression was cysticercosis (vesicular stage)
in the left parotid region.
The patient underwent detailed neurology and ophthalmology
review which were unremarkable. NCCT brain revealed no
significant neuroparenchymal abnormality. Patient was managed
conservatively with tablet Albendazole once daily for 21 days
and advised a high fibre low protein diet. After the completion of
anthelmintic pharmacotherapy, the swelling significantly reduced
in size. Further a follow up ultrasonography revealed no evidence
of any cystic lesions in the head and neck. After 3 months of follow
up there was no evidence of residual or recurrent disease (Figure
2). The patient is currently doing well.
Cysticercus cellulose is the larval form of Taenia solium and
presents as a larval infection produced by the cestodes . The
causative parasite of cysticercosis passes its life cycle in two
hosts: Human is the definitive host as the adult worms live in the
small intestine [1,2]. The intermediate host is pig which shelters
the larval stage and cause cysticercosis. Human beings acquire
cysticercosis through feco-oral contamination with Taenia solium
eggs from tapeworm carriers [3,5,6]. Therefore, vegetarians and
people who don’t eat pork can acquire this infection. Water, wind,
flies and other indirect means of infection play some part in its
An adult worm measures 3 meters in length with 1000
proglottids each of them containing approximately 50,000 eggs.
The adult worm sheds their eggs in stool which are taken up by
pigs and acts as the intermediate host. In the alimentary canal of
the intermediate host, these eggs rupture and oncospheres are
produced. The oncospheres penetrate the gut wall of pigs and
reach their systemic circulation and enters various organs and
muscles. It is over here that encystment of larval forms takes
place and is termed as cysticercosis cellulose. The larval forms
enter humans by the ingestion of contaminated food or water. The
transmission of eggs via hands or carriers of the adult worm or
internal autoinfection by regurgitation of eggs into the stomach
can also lead to infection [6,7].
The larval forms reach subcutaneous tissue, muscles, brain
and ocular tissues via blood vessels and lymphatics. Clinically, the
patient may remain asymptomatic or present with epigastric pain,
nausea and diarrhoea. Sometimes, these larval encystment occur
in oral and facial region. In majority of cases, cysticercosis presents
with a solitary nodule and can be noted on trunk, upper arm, eyes,
neck and rarely tongue, face and breast. In neurocysticercosis,
the patient present with seizures and can be associated with skin
Radiological findings are not routinely used in the diagnosis of
cysticercosis. The cysticercus cyst present with an inflammatory
mass around it, irregular cyst with minimal fluid on one side and
may appear as a large irregular collection of exudative fluid or seen
as calcified mass . FNAC and high-resolution ultrasonography
are helpful in the diagnosis of cysticercosis. The patient should
also be screened for any ocular and neurological involvement.
The presence of fragment of larval bladder wall, hooklets and
calcareous corpuscles confirms the diagnosis of cysticercosis. The
background may be granular and reveal eosinophils, neutrophils,
palisading histiocytes, giant cells. On ultrasonography it may
appear as a cysticercus cyst with an inflammatory mass around
it, as an irregular cyst with very minimal fluid on one side.
Cytologically, other differential diagnosis which can be kept in
mind are hydatid cyst which shows presence of protoscolices,
hooklets, and fragments of the laminated membrane. In some
cases, only laminated membranes are present in the inflammatory
background. Cysticercosis must also be differentiated from
abscesses and non-parasitic cysts [10-12].
Computed tomography (CT) and magnetic resonance
imaging (MRI) have greatly improved the accuracy of diagnosis
of cysticercosis. The vesicular stage of the cyst is seen on the CT
as a hypodense area containing a hyperintense small scolex along
with a nonenhancing or mildly enhancing cyst wall (Figure 3).
CT depicts the colloidal vesicular stage as a ring enhancing cystic
lesion with hyperintense fluid content and surrounding edema.
In the granular nodular stage when the cyst retracts to form a
nodule, the CT shows an enhancing nodule with mild surrounding
edema. The final stage can be seen as single or multiple calcified
nodules. MRI is considered best for the detection of a degenerating
and innocuous (viable) cysticerci. It also helps in visualizing the
perilesional edema very well. Hence, although MRI allows better
detection of the active parasites, it can miss the calcified lesions,
especially when the gradient echo sequence is not used; in which
case a CT must be advised .
The standard treatment for facial or muscular cysticercosis
is prescription of anthelmintic drugs like praziquantel and
albendazole. Sometimes, corticosteroids such as prednisolone
can be used in cases where there is associated inflammatory
reaction. Effective preventive measures can also be taken like
consumption of high fibre diet, well-washed vegetables, filtered
or boiled water and proper hand washing before meals and
preparation of food. Hence, medical management can heal most
of the symptomatic lesions and surgery is not always required in
muscular cysticercosis [10,11].
Lesions in the facial region are uncommon, but cysticercosis
should be kept as a clinical differential diagnosis in concurrence
with dietary history and radiological findings. It is a global health
problem with high prevalence in endemic countries like India.
Improvement in the sanitary conditions, adequate treatment of
sewage or feces, and educating public about personal hygiene
such as hand washing can help in the prevention of human
Previous studies have suggested FNAC and USG to be quick
mode of investigation in diagnosing clinically unsuspected case of
cysticercosis of facial region, but reports suggested that CT and
MRI proved to be equally reliable diagnostic tools for the diagnosis of cysticercosis in the absence of a definitive pathological
diagnosis as they help in assessing the relation of cyst to the
surrounding structures and more effective in identifying cyst and
scolex. Therefore, an early anthelmintic therapy (albendazole
15mg/kg/day) can be started for 21 days that leads to the healing
of most of the symptomatic lesions and the need for surgery can
be avoided in case of muscular cystecercosis. However, the patient
should be followed up for monitoring of therapeutic response and
ophthalmologic or neurologic signs of cysticercosis cellulose to
prevent any complications with the help of a CT or USG.