Atypical Head and Neck Cysticercosis: Diagnostic Pitfalls and Clinical Insights from a Case Series and Literature Review

Abstract

Head and neck swellings encompass a broad range of differential diagnoses, often necessitating comprehensive clinical and diagnostic evaluations to reach an accurate diagnosis. Cysticercosis, a parasitic infection caused by the larval form of Taenia solium, typically affects neural and extraneural regions. Although neural manifestations are well-documented, extraneural cysticercosis in the head and neck is rare and can mimic neoplastic and inflammatory conditions, posing diagnostic challenges. This study presents a series of cases of atypical head and neck cysticercosis, including unique presentations in regions like the parotid gland, tongue, and neck muscles, which were initially mistaken for other common pathologies. Through a detailed analysis of imaging findings and histopathological examinations, this article highlights diagnostic pitfalls and emphasizes the importance of considering cysticercosis in differential diagnoses, especially in endemic regions. This case series, supported by a systematic review of literature, underscores the need for heightened clinical awareness to prevent misdiagnosis and ensure timely management of this rare but significant condition.

Introduction

Head and Neck swelling can have a wide range of differential diagnoses, which vary based on factors such as the patient’s age, the precise location of the swelling, the duration of symptoms, the clinical progression, and the characteristics of the mass. In a middle-aged adult, a swelling located in the posterior triangle of the neck is commonly associated with conditions such as nasopharyngeal carcinoma, lymphoma, metastatic lymph node involvement, tubercular lymphadenitis, and less frequently, other chronic infections. Cysticercosis, a parasitic infection caused by the larval form of Taenia solium, occurs when humans, serving as accidental hosts, ingest the eggs of this tapeworm. The condition can manifest in two main forms: neural and extraneural. The neural form, known as neurocysticercosis, affects the central nervous system and is a well-recognized cause of neurological symptoms. The extraneural form typically affects the eyes, skeletal muscles, and subcutaneous tissues, presenting as single or multiple firm nodules that are subcutaneous or submucosal.In the context of the head and neck, cysticercosis is considered a rare entity. Documented cases have described cysticercosis manifesting as soft tissue swellings in areas such as the submental region, the cheek, and the oral tongue [1, 2]. These presentations are important for clinicians to recognize, as they can mimic other, more common causes of head and neck masses.

Methodology

This research was conducted as a case series analysis supplemented by a review of the existing literature on head and neck cysticercosis. It combines retrospective patient data from clinical records and a literature review on atypical presentations of head and neck cysticercosis challenge existing diagnostic protocols, and what are the implications for early and accurate diagnosis.

Case Series

Patients were selected from clinical records of the ENT department at Patna Medical College and Hospital over a specified period of two years. The inclusion criteria included patients diagnosed with cysticercosis in the head and neck region, confirmed by imaging (USG, MRI, or CT) and/or histopathology. Cases with incomplete records or insufficient diagnostic evidence were excluded.

Data Collection

Clinical data included demographic information such as age and gender, a detailed patient history encompassing onset, duration, symptoms, and family history. Physical examination findings were documented, noting the size, location, and characteristics of the swelling, along with any associated symptoms like pain, fever, or functional impairment. Diagnostic investigations were reviewed and detailed, including imaging findings (e.g., characteristics observed on USG or MRI) and results from FNAC or biopsy.

Review of Literature

A literature search was conducted using databases such as PubMed, Embase, Pubmed Central, and Google Scholar. The search focused on all available studies related to head and neck cysticercosis, employing search terms like “head and neck cysticercosis,” “myocysticercosis,” “neck cyst,” and “oral cysticercosis.” Inclusion criteria encompassed case reports, case series, and reviews that described human cases of head and neck cysticercosis with sufficient clinical and diagnostic detail. Studies focusing on cysticercosis outside the head and neck region or those without full-text access were excluded from the review.

Case Series

Case 1: Swelling in the Right Parotid Region

A 22-year-old female presented with a swelling on the right side of the parotid region(Fig. 1). The patient first noticed a painless, pea-sized swelling approximately 10 years ago, which gradually increased in size over the next five years. As the swelling grew, she began experiencing mild pain that progressively worsened. She now reports significant discomfort, particularly during jaw movements, such as opening and closing the mouth.

Fig. 1.

22-year-old female presented with a swelling on the right side of the parotid region

The patient’s family history is notable for her father having had painless swellings on his hand, forearm, and arm, suggesting a potential hereditary component.

On physical examination, a 2.5 cm × 1.5 cm swelling was noted in the right parotid region. The overlying skin appeared normal, with no discoloration or changes. On palpation, the mass was firm, mildly tender, and not fixed to the underlying tissues. A dynamic examination revealed that the swelling became more prominent when the jaw was clenched.

Imaging investigations included an ultrasound (USG) of the swelling, which showed a well-defined hypoechoic cystic lesion measuring 7.5 mm × 2.9 mm within the muscular plane of the masseter muscle. The lesion displayed eccentric calcifications casting posterior acoustic shadowing. Magnetic Resonance Imaging (MRI) revealed multiple well-encapsulated cystic lesions with mural eccentric nodules and surrounding edema within the right masseter muscle. These findings were highly suggestive of cysticercosis.

Fine-Needle Aspiration Cytology (FNAC) of the lesion yielded clear, watery fluid. Microscopic examination of the aspirate identified fragments of the larval form of Taenia solium, known as cysticercus cellulosae. The smears also showed an inflammatory infiltrate composed of polymorphonuclear leukocytes, lymphocytes, histiocytes, and occasional plasma cells, confirming the diagnosis of cysticercosis.

Case 2: Tongue Swelling

A 27-year-old female presented to the ENT outpatient department with a complaint of swelling and discoloration of the right side of the tongue(Fig. 2). The swelling had been progressively increasing in size over the past two years. She described a mild, continuous pain associated with the swelling, with no specific aggravating factors. The patient denied any difficulty in swallowing (dysphagia) or trismus (difficulty in opening the jaw). There was no significant family history or prior medical history relevant to her condition.

Fig. 2.

27-year-old female with a complaint of swelling and discoloration of the right side of the tongue

On examination, a soft-to-firm, fluctuant, mildly tender swelling was noted on the right side of the tongue. The swelling was associated with mild systemic symptoms, including continuous low-grade fever. There was no evidence of significant oropharyngeal involvement or other concerning signs on general physical and systemic examination.

Investigations

Ultrasound (USG) of the Tongue: Revealed a well-defined, hypoechoic, cystic lesion measuring 2.3 × 1.7 mm within the muscular planes of the right side of the tongue. The findings were suggestive of cysticercosis.

Magnetic Resonance Imaging (MRI): Demonstrated a well-defined T2/STIR hypointense lesion of size 2.3 × 1.7 mm in the intrinsic muscle of the right side of the tongue, consistent with cysticercosis.

Case 3: Neck Swelling

A 45-year-old male presented to the ENT outpatient department with a complaint of a right-sided neck swelling (Fig. 3). The swelling had been present for the past nine months and was painless, progressively increasing in size over time. The patient denied any associated symptoms, including difficulty with neck movements, dysphagia, or dyspnea.

Fig. 3.

45-year-old male with right-sided neck swelling

On physical examination, there was a well-defined swelling measuring 3 cm x 2 cm on the right side of the lower third of the sternocleidomastoid (SCM) muscle.

The swelling was firm, non-tender, and not fixed to underlying structures, with no overlying skin changes or signs of inflammation.

Investigations

Ultrasound (USG) of the Neck Swelling: Revealed a hypoechoic cystic lesion measuring 5 × 4 mm in the subcutaneous plane anterior to the right SCM. The lesion was surrounded by thick, inflamed subcutaneous fat, with fine internal echoes noted within the cyst. The findings were suggestive of cysticercosis (Fig. 4).

Fig. 4.

USG Neck revealed a hypoechoic cystic lesion suggestive of cysticercosis

Case 4: Trismus at Presentation

A 32-year-old male presented to the ENT outpatient department with a complaint of progressive difficulty in opening his mouth over the past six months. He reported intermittent jaw pain, which was more pronounced during chewing and speaking. The pain was described as moderate and exacerbated by masticatory movements. There was no associated swelling noticed by the patient, and he did not report any history of trauma, fever, weight loss, or other systemic symptoms. The patient mentioned that his symptoms had gradually worsened, prompting him to seek medical attention. His medical and surgical history was unremarkable, and he denied any significant family history of similar complaints. The patient worked in a desk job and had no occupational exposures that could account for his symptoms.

On physical examination, the patient had trismus, with a reduced mouth opening of approximately 20 mm. Palpation of the masticatory muscles, including the masseter and temporalis, did not reveal any visible or palpable swelling. There was tenderness elicited on palpating the region of the pterygoid muscles, particularly during active jaw movement. Examination of the oral cavity and oropharynx was unremarkable, with no mucosal lesions or signs of infection. The rest of the head and neck examination, including lymph node assessment, was within normal limits.

Ultrasound (USG) of the masseter and pterygoid muscles did not reveal any obvious cystic lesions in the masseter muscle; however, deeper imaging was limited.

Magnetic Resonance Imaging (MRI) identified a well-defined, encapsulated cystic lesion in the right pterygoid muscle, measuring 10 mm × 8 mm. The lesion exhibited characteristic features of cysticercosis, including a hyperintense cyst on T2-weighted images with a hypointense eccentric nodule, consistent with the scolex (Fig. 5).

Fig. 5.

MRI shows well defined encapsulated cystic lesion in the right pterygoid muscle

Literature Review

Atypical presentations of head and neck cysticercosis pose significant challenges to existing diagnostic protocols, often leading to misdiagnosis and delayed treatment. This review explores the diagnostic difficulties associated with these uncommon manifestations and discusses their implications for early and accurate diagnosis (Table. 1).

Table 1.

Case Series Data on Atypical Head and Neck Cysticercosis

Case no.	Age/Sex	Location of swelling	Duration of symptoms	Symptoms	Size of swelling	Imaging findings	Diagnosis method
1	22/Female	Right Parotid Region	~ 10 years	Mild pain, worsened over time; discomfort during jaw movement	2.5 cm x 1.5 cm	USG: 7.5 mm x 2.9 mm hypoechoic cyst with calcifications; MRI: Multiple cysts in masseter muscle	FNAC confirmed cysticercosis
2	27/Female	Right Side of Tongue	~ 2 years	Mild continuous pain, low-grade fever	2.3 mm x 1.7 mm	USG: Hypoechoic cyst; MRI: T2 hypointense lesion in intrinsic muscle	Imaging findings suggestive of cysticercosis
3	45/Male	Right Neck (SCM Region)	~ 9 months	Painless, progressive increase in size	3 cm x 2 cm	USG: Hypoechoic cyst with internal echoes	Imaging findings suggestive of cysticercosis
4	32/Male	Right Pterygoid Muscle	~ 6 months	Trismus, moderate jaw pain, aggravated by movement	10 mm x 8 mm	MRI: Encapsulated cyst in pterygoid muscle	Imaging findings consistent with cysticercosis

*A table summarizing the key data from the case series on atypical head and neck cysticercosis

Head and neck cysticercosis can present in various atypical forms that mimic other pathologies, complicating clinical assessment and management. For instance, cysticercosis can manifest as isolated swellings within muscles such as the masseter or temporalis, often resembling neoplastic or inflammatory lesions. A case involving a 16-year-old female described a progressively enlarging, painful swelling over the right temple region. It was eventually diagnosed as a solitary cysticercus in the right temporalis muscle after thorough investigation [3]. Similarly, cysticercosis in the parotid area may be misdiagnosed as salivary gland tumors or lymphadenopathy due to its similar presentation. A study documented a case where a swelling in the parotid region was initially suspected to be a neoplasm. Further diagnostic evaluation, however, revealed it to be cysticercosis [4]. Additionally, cysticercosis can present as a mass in the tongue, floor of the mouth, or buccal mucosa, which is exceedingly rare and often misdiagnosed as benign or malignant tumors of the oral cavity, highlighting the diagnostic challenge they pose [5].Masseter muscle involvement is another atypical presentation where patients often report painful jaw swelling that worsens with chewing or jaw movements. These symptoms can be mistaken for conditions like parotid gland pathologies or temporomandibular joint disorders. An article reported a case of a 40-year-old woman with progressive jaw pain and swelling localized to the masseter region. MRI imaging confirmed cysticercosis, and the diagnosis was validated through FNAC, which demonstrated the presence of cysticercus larvae [6] [7]. Cysticercosis in the parapharyngeal space can present as difficulty swallowing, a sensation of a mass in the throat, or voice changes, symptoms that often mimic deep neck space infections or tumors, posing a diagnostic challenge for clinicians [8].

Imaging plays a pivotal role in diagnosing cysticercosis, but atypical presentations can make interpretation difficult. Ultrasound (USG) typically reveals hypoechoic cystic lesions with internal echoes. However, in atypical cases, these features may be nonspecific. A comprehensive review emphasized that cysticercosis can present with a range of imaging findings, making it hard to distinguish from other cystic lesions [9]. Magnetic resonance imaging (MRI) can reveal well-defined cystic lesions with surrounding edema, providing more detailed anatomical information. Despite this, distinguishing cysticercosis from other cystic or neoplastic lesions can be challenging. A case report highlighted the diagnostic difficulty posed by neurocysticercosis, where varied imaging appearances complicate the identification process [10].

Histopathological examination remains the definitive method for diagnosing cysticercosis, as emphasized by Brown et al., who described it as the most reliable diagnostic tool [11]. Both FNAC and histopathology have their roles and limitations. FNAC is a minimally invasive technique that can yield diagnostic material, but its effectiveness depends on the lesion’s accessibility and the presence of distinctive features. A study on head and neck cystic lesions reported challenges in cytological diagnosis due to overlapping characteristics with other conditions, complicating interpretation [12]. On the other hand, surgical excision followed by histopathological examination can confirm the diagnosis of cysticercosis. However, this method is invasive and not always feasible. In some instances, histopathological analysis has revealed cysticercosis in lesions initially suspected to be malignant, underscoring the importance of considering parasitic infections in the differential diagnosis [13].

Atypical presentations of head and neck cysticercosis often result in misdiagnosis, leading to unnecessary treatments or delays in appropriate therapy. Increased clinical awareness and consideration of cysticercosis in the differential diagnosis are essential, particularly in endemic areas. The condition is frequently overlooked as a potential cause of head and neck masses, posing a significant diagnostic and therapeutic dilemma for clinicians. Early recognition and accurate diagnosis are crucial to prevent mismanagement and to initiate appropriate treatment promptly.

Final Comments

This article highlights the significant diagnostic challenges posed by atypical presentations of head and neck cysticercosis. The varied clinical manifestations often mimic neoplastic or inflammatory conditions, complicating diagnosis and leading to potential mismanagement or delayed treatment. Through a detailed analysis of case studies and evidence from literature, it becomes clear that early recognition and a high index of suspicion are essential, particularly in endemic regions. Improved awareness among clinicians, combined with the strategic use of imaging and cytological techniques, can facilitate timely and accurate diagnosis. Ultimately, this review underscores the need for a multidisciplinary approach and the inclusion of cysticercosis in the differential diagnosis of head and neck masses to optimize patient outcomes.

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