Clinical Profile of Cysticercosis in Head and Neck

Objectives: Review of the various clinical presentations of cysticercosis in head and neck and its diagnosis. Materials and Methods: Data Sources: PubMed was searched with MeSH terms Cysticercosis, Oral cavity, Tongue, Buccal, Lip Cheek, Neck, Muscle neck, Muscle head, Parotid, gland, Fnac, Larynx, Pharynx, Nose, Ear, Orbit, Ocular. The results were extensively reviewed to select relevant articles of isolated lesions of head and neck (other than brain) which present to clinician as a diagnostic dilemma. Review Methods: Articles generated were oral cavity(98), Tongue(128), Buccal(12), Lip(20), Cheek(9), Neck(58), Muscle neck(21), Muscle head(26), masseter(29), Temporalis(6), Parotid(11), gland(38), Fnac(19), Larynx(3), Pharynx(6), Nose(9), Ear(20), Orbit(59), Ocular(166). Out of these, 118 unique articles were selected, accessed, references reviewed to finally study 109 relevant articles. These have been studied for clinical presentation and how clinical problem was solved. Review Article Rathi et al.; IJTDH, 13(3): 1-12, 2016; Article no.IJTDH.23606 2 Implications for Practice: Cysticercosis is usually a diagnostic dilemma in head and neck, and the diagnostic tools used in such clinical scenario, are well known, easily available and dependable. These tools like fine needle aspiration cytology and sonography, however are not the part of diagnostic criteria. Their accuracy, utilisation, and vast availability suggest their role needs addition in present diagnostic criteria. Conclusion: Cysticercosis is the major neglected tropical disease. High vigilance and prompt diagnosis is required for adequate management of this eradicable disease. Various presentations in head and neck have been described. Diagnosis based on present criteria is not always possible. Well known investigations are helpful in early and accurate diagnosis.


INTRODUCTION
Extra cranial cysticercosis is a well known entity with increased incidence due to global migration of disease. Further, increased awareness and health seeking behaviour brings more such presentations to physician.
Its clinical presentation has a huge differential diagnosis including neoplastic lesions. Lack of awareness about various clinical presentations increases the diagnostic dilemma. Diagnostic criteria used for management is same for neurocysticercosis and extra cranial lesions. Fine Needle Aspiration Cytology (FNAC) and sonography are not done in neurocysticercosis, whereas they are frequently used in extracranial lesions. This increases difficulty in management, as they are not a part of diagnostic criteria, yet they can give definite diagnosis.

Objective
Review the spectrum of presentations of cysticercosis and its diagnosis in head and neck.

MATERIALS AND METHODS
Search made in PubMed with MeSH terms Cysticercosis, oral cavity, Tongue, Buccal, Lip Cheek, Neck, Muscle neck, muscle head, Parotid, gland, FNAC, Larynx, pharynx, Nose, Ear Orbit, Ocular of all time (Till 30-12-2014). Only articles related to humans of English literature were selected. These results were extensively reviewed to select only articles of isolated lesions of head and neck (other than brain) which present to clinician as a diagnostic dilemma. Disseminated lesions and articles with associated multiple subcutaneous nodules, known neurocysticercosis have been excluded. Also articles lacking the above details were excluded.

RESULTS
Articles generated were Oral cavity(98), Tongue(128), Buccal (12), Lip (20), Cheek (9), Neck (58), Muscle neck (21), Muscle head (26), Masseter (29), Temporalis(6), Parotid (11), gland (38), FNAC (19), Larynx(3), Pharynx(6), Nose (9), Ear (20), Orbit (59), Ocular(166). Out of these, 118 unique articles of diagnostic dilemma were selected, accessed, references reviewed to finally study thoroughly 109 relevant articles (see Figs. 1,2). It was declared eradicable by the International Task Force for Disease Eradication in 1993, but still remains a neglected disease and was added by World Health Organization (WHO) to the list of major neglected tropical diseases in 2010 [2]. Experience at Peru shows detection and treatment forms one of the main component for control and interruption of transmission of cysticercosis. Thus practising otolaryngologist becomes a part of eradication team by helping diagnosis and adequate treatment. Therefore awareness of spectrum of cysticercosis is important, which is not much reported in the literature.  Almost all age groups are affected ranging from 2 to 78 years, although less than 30 years is considered at more risk. No sex predilection is noted with equal incidence in males and females. Data analysis of minimum five years duration from endemic areas shows incidence of cysticercosis in head and neck (H&N) ranging from 24.08% -27.2% on FNAC studies and 9.5% -22.23% on Histopathological examinations (HPE) [4][5][6][7]. Most common site in H&N is neck followed by oral cavity.

Cysticercosis is the infection caused by
Though cysticercosis is more common in nonvegetarians (pork-eaters), it is also seen in vegetarians. History of residence or travel in an endemic area is usually present. Symptoms due to neurocysticercosis or disseminated cysticercosis; if present help in diagnosis. An asymptomatic, isolated cyst may remain undetected until it enlarges, migrates and dies and produces symptoms or may be incidentally detected.
Neurocysticercosis has no specific symptom or sign; however epilepsy is the most common manifestation. Others

Neck
Head and Neck is second most common site for cysticercosis presenting as subcutaneous nodules (Table 1). It presents as soft-firm, mobile, non-tender nodule which is clinically diagnosed as lipomas, neurofibromas, or lymphadenopathy [5].
On FNAC identification of larvae by different workers, has made it first investigation of choice in skin nodules. It may present as single or multiple nodules increasing the list of differential diagnosis. Solitary lesions in midline or lateral part of neck are also known involving lymph nodes and muscles like sternothyroid, SCM (SternocleidoMastoid), trapezius, mylohyoid. Involvement of sub-mental region and submandibular region including sub-mandibular gland and duct is also reported [9][10][11][12][13][14][15][16][17][18].
Involvement of thyroid has been reported along with other systems, although Pradeep PV, et al. [19][20][21] reported presentation as thyroglossal duct cyst which was diagnosed post operatively.
Uledi SJ [22] reported a case presenting as long standing giant solitary pseudotumor of neck which was diagnosed as cysticercosis. Jain S, et al. [23] reported a racemose form of cysticercosis in neck presenting as soft cystic swelling of size 6 cm× 7 cm in the right supraclavicular region.

Oral Cavity and Pharynx
Muscles of oral cavity are most commonly involved than other masticatory and neck muscles. A total of 94 cases of cysticercosis involving various sites of oral cavity were found in English literature, excluding cases in which cysticercosis was suspected clinically due to involvement of other sites, and cases without adequate data. Previous study including other language searches showed 97 overall cases reported in literature [24].
For a clinician, cysticercosis of oral cavity is constantly a diagnostic problem because of its rarity. It is seldom a provisional diagnosis by the treating physician. When present, it frequently involves tongue, labial or buccal mucosa and floor of mouth, although gingiva, and retromolar trigone are also reported [25]. Intraorally, they present as painless, submucosal nodules or cystic mass, usually progressively increasing, tongue being most commonly involved. On examination a solitary, firm or cystic, non-tender, non fluctuant nodular mass is usually noted with overlying normal mucosa. Movements of tongue are usually preserved without any difficulty in eating or swallowing. Rarely, large lesions on dorsal aspect of tongue or inner aspect of lip can cause discomfort [3].
Though pain is not a frequent feature, it had been reported in secondarily infected cases. Cervical nodes are not involved in isolated cases. Mucous retention cyst is usually the first differential diagnosis, others being fibroma, leiomyoma, dermoid cyst, lipoma, a benign lesion of salivary gland or neural origin [24].

Pharynx
Mahindra S, et al. [14] reported an adult female presenting with pain in throat with a swelling on left side of soft palate, without systemic involvement. Sobnach S, et al. [26] reported an elderly female who presented with altered speech and multiple subcutaneous nodes.

Muscles of Head and Neck
Cysticercosis cellulosae, the encysted larval form of T. solium can remain viable in various sites for as long as 10 years in humans [27]. Living larvae escape immune recognition and do not elicit inflammation. However when the larva dies, a vigorous granulomatous inflammatory response is induced comprising predominantly of plasma cells, lymphocytes, eosinophils and macrophages [28]. Later, in long standing cases, the dead cyst is surrounded by a dense layer of fibrosis or calcification.
In muscular involvement, three distinct types of clinical manifestations have been described: the myalgic type; the mass-like, pseudo-tumour or abscess-like type; and the rare pseudohypertrophic type. Leakage of fluid from the cyst during death of larva induces acute inflammation resulting 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 type, the pseudo-tumour type or the abscess-like type [29].

Masticatory Muscles
A total of 17 cases have been reported till date involving masticatory muscles of which 10 has been diagnosed by radiology alone and other 5 have been supported by pathology, 2 by serology ( Table 2).

Masseter
Solitary involvement of masseter muscle presents as bimanually palpable non-tender, nodular, firm, mobile, gradually increasing swelling. Facial symmetry is undisturbed unless swelling becomes large. It may present as acute inflammation with tender swelling [30]. It is usually diagnosed as inflammatory lesion of salivary gland or salivary neoplasm, with differentials including primary and metastatic tumours of masseter muscle, sarcoidosis, lipomas, solitary neurogenic tumours and vascular lesions. In fact we had a case with clinically palpable nodule in parotid region diagnosed as cysticercosis on FNAC but turned out as masseter lesion on radiological work up. Therefore we suggest compulsory radiological work up in cysticercosis nodules for definite anatomical site [31][32][33]. Gupta S, et al. [34] reported a rare presentation of masseter involvement with generalised on and off urticaria.

Temporalis
Isolated involvement of temporalis usually presents as painful tender swelling with associated headache. Pain may aggravate on chewing and or application of pressure. History of gradually increasing chronic swelling is usually elicited [35][36][37].

Pterygoid
Virk et al. [38] noted isolated involvement of pterygoid muscle, which presented with trismus due to pain.
Though patients of cysticercosis of masticatory and other deep seated muscles are not aware of lesion, asymptomatic presentation of a muscle swelling, usually masseter is noted due to visibility, increasing health awareness and health seeking behaviour of people.

Salivary Gland
Signs and symptoms of cysticercosis depend on the site of involvement and the stage of evolution. However, the most common presentation is swelling at the affected site. Solitary parotid lesion may present as slowly growing mass softfirm in consistency in the pre-auricular region and cheek, which can also be due to masseter involvement. It is commonly misdiagnosed as soft-tissue tumor. When symptomatic, differential diagnosis includes acute parotitis, parotid abscess, parotid sialadenitis, subcutaneous tissue abscess, pyomyositis or lymphadenitis [32]. Submandibular gland and lymph node when involved can present as painful swelling or may be diagnosed accidentally. Swelling in this area due to muscle involvement may be misdiagnosed, again citing the importance of radiological investigations [16].

Ear
A person presenting with sensory neural type hearing loss with headache may have cysticercosis involving cerebellopontine angle [39]. Post aural gradually increasing swelling close to mastoid tip has been reported without any other symptoms [14].

Nose and Paranasal Sinuses
It can present as chronic swelling over nasal dorsum, without any symptoms which may be diagnosed as Nasal dermoid [40]. Though many cases have been reported for isolated eyelid involvement presenting as swelling, these can be due to involvement of supra-orbital frontal bone [41].

Larynx
Only two cases reported with presentation of progressive hoarseness with cystic mass bulging from false and true vocal cords which were diagnosed postoperatively as cysticercosis [42,43].

Orbit
Ocular and adnexal cysticercosis represents 13-46% of systemic disease with prevalence of 0.10%. Unilateral involvement with predilection for left eye has been observed more commonly [44,45]. Spectrum of clinical presentations depend on the site of lodgement, size of cyst, host immune status and level of inflammatory reaction. Primary site of involvement varies with intraocular being predominant in western countries, whereas extraocular more common in Indian population [45]. Most favoured sites for intraocular cysticercosis are subretinal and vitreous cavity where they gain access through posterior ciliary arteries while orbital cysticercosis commonly shows subconjunctival space and extraocular muscle involvement [44,45]. Various clinical symptoms of ocular cysticercosis can be either due to inflammatory reaction evoked by viable cyst or due to compression of surrounding structures by mature cyst. Most commonly described are blurring of vision, restriction of ocular motility, proptosis, diplopia, acquired ptosis, strabismus, subconjunctival cyst, eyelid erythema and nodule [44,45]. There can be direct visualization of clinically evident cyst in anterior chamber and vitreous cavity or ultrasonographic evidence of characteristic appearance of the cyst [47]. In earlier stages in intraocular disease, signs of severe uveitis, retinal edema, haemorrhage, retinal & vitreous proliferation, exudative retinal detachment are present while retinal necrosis and atrophy are noted in later stages [44][45][46][47]. Unusual presentations of cysticercosis described in the literature are pupillary block glaucoma, endogenous endophthalmitis, orbital cellulitis, pseudotumour, subperiosteal cyst, atypical optic neuritis involving optic disc and optic canal, obstruction of lacrimal gland as well as lacrimal canaliculi and masquerading as retinoblastoma or optic nerve glioma [48][49][50][51][52][53][54][55][56][57]. Bilateral multifocal involvement or brown syndrome with bilateral superior oblique muscle involvement has also been described in literature [58,59].
An increased awareness of the typical and atypical presentations coupled with high index of clinical suspicion, may help in early diagnosis. Early presentation to the ophthalmologist and early intervention with extremely effective treatment while inflammation is relatively mild leads to resolution in most patients and more favourable visual outcome.

Diagnosis
Cysticercosis is rarely in the list of differential diagnosis due to its diverse non-specific presentations. The benign behaviour of such lesions seldom present to clinician unless lesions increases in size or cause symptoms due to various reasons. It may also be detected accidentally while investigating for other purpose.
Del brutto et al gave criteria for diagnosis of Human cysticercosis (HC) to aid in its diagnosis in endemic areas, where modern diagnostic techniques are infrequently available [60]. They suggested four degrees of criteria based on clinical, radiological, immunological and epidemiological data, with three diagnostic possibilities a) definitive b) probable c) possible.

Sonography
Sonography is initial modality of choice for soft tissue swelling, more so in resource limited countries. HC is being increasingly diagnosed reliably with easily available high frequency ultrasonography. This is based on demonstration of sonographic features especially scolex in the lesion, sensitivity and specificity of which depends on expertise, thorough scanning, and stage of disease. On sonography four appearances have been described [29]. These include (a) cysticercus cyst with surrounding inflammatory mass, (b) an irregular cyst with very minimal fluid on one side, (c) a large collection of exudative fluid, with the typical cysticercus cyst containing the scolex, (d) calcified cysticercosis.

FNAC
FNAC is diagnosis of choice for subcutaneous nodules, where there are many differential diagnoses. Considering series of more than hundred cases arbitrarily, using FNAC for definitive diagnosis has shown sensitivity from 46.4% to 94.2% [4,5]. Rest cases were diagnosed as suspicious of parasitic infestation, which on histopathological examination has very high sensitivity though never 100%. The reason for this may be due to variations in host-body reactions and stage of evolution of cyst. Various spectrums have been described though FNAC or biopsy require visualisation of the detached hooklets, scolex, and fragments of the bladder wall of Cysticercosis cellulosae [5].

Serology
Hematological profile often remains unaltered though eosinophilia may be noted when there is leakage of parasitic antigen into surrounding tissues. Using serological methods sensitivity of antibody testing tends to be high for cases with multiple cysts (

Radiology
If the cyst is calcified, routine imaging (X-ray) can detect it. For soft tissue involvement, plain films reveal multiple calcified "puffed-rice" lesions [28].

Management
Surgical excision is the treatment of choice in extracranial cysticercosis including intraocular lesions except intraorbital cysticercosis where medical treatment is preferred [43][44][45]. Excision clears the disease in isolated lesions and also provides specimen for definite diagnosis. On contrary, presence of intraocular cysticercosis is a contraindication for systemic antihelmenthic drugs as intraocular death of worm causes intense blinding panuveitis [64]. Medical management is given in inaccessible symptomatic lesions, with corticosteroids and antiparasitic therapy, though role of antihelminthic drugs is not proven in single extracranial cysticercosis [44]. Few authors even suggest wait and watch for asymptomatic lesions, however treatment is advised in insidious, silent but morbid course of disease. For cysticercosis, Praziquantel is given at 50mg/kg/day for 15 days and Albendazole at dose of 15mg/kg body weight for one month [2]. WHO recommends praziquantel (10 mg/kg body weight orally) and niclosamide (2 g orally) for human taeniasis with dexamethasone 0.1 mg/kg/day for associated inflammation [1]. Ruling out neurocysticercosis is must, as antihelminthics can exacerbate seizures in silent lesions (known risk with praziquantel). Prognosis of head and neck soft tissue cysticercosis is excellent with no recurrence, in contrast to other cerebral, ocular, cardiac sites.

Implications for Practice
Cysticercosis is usually a diagnostic dilemma in head and neck. High vigilance is required for its diagnosis and adequate management, to eradicate this neglected global disease. Sonography and FNAC are easily available, accurate, affordable, and solves clinical scenario in a better way. They are to be studied further, to define sensitivity and specificity, considering their role in diagnosis.

CONCLUSION
Cysticercosis, aptly said as modern day plague, is the major neglected tropical disease [65]. Soft tissue cysticercosis is known to be present in 54% of infected people, however neurocysticercosis presents more to the clinician [66]. High suspicion and prompt diagnosis is required for adequate management of this eradicable disease. Various presentations have been described and changes in diagnostic criteria have been suggested with reliable and easily available methods, which can even be used in resource limited endemic areas.

CONSENT
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ETHICAL APPROVAL
It is not applicable.