Thyroid abscess as a primary presentation of tuberculosis: a case report

Abstract

Introduction:

Thyroid tuberculosis (TB) is infrequently reported even in regions with high TB prevalence, due to the gland’s inherent resistance and nonspecific clinical presentations. Involvement of the thyroid gland in extrapulmonary TB is an uncommon occurrence. It can manifest as various thyroid conditions, making timely diagnosis challenging and necessitating a high level of clinical suspicion. This report presents a case of thyroid cold abscess caused by TB. The goal is to raise awareness among clinicians about this possibility and to emphasize its clinical management.

Case Presentation:

This study presents a case of a 14-year-old girl diagnosed with a tubercular thyroid abscess. Clinical examination, imaging, and fine-needle aspiration (FNA) cytology confirmed the diagnosis, revealing granulomatous inflammation consistent with TB. This case underscores the diagnostic challenges posed by thyroid TB due to its mimicry of malignancies and other thyroid pathologies. FNA biopsy and imaging are critical tools for diagnosis. Though antitubercular therapy (ATT) remains the primary treatment, surgical intervention is necessary in some cases. Awareness of this rare condition is essential for timely diagnosis and management, particularly in endemic regions.

Discussion:

Thyroid TB should be considered in patients presenting with non-tender, cold nodules, especially in high-risk populations, including those with comorbidities or from TB-endemic areas. A thorough history and examination are crucial to identifying atypical extrapulmonary manifestations. This discussion underscores the importance of clinical vigilance and a multidisciplinary approach to managing this rare and complex condition.

Conclusion:

Tubercular thyroid abscess is an exceptionally rare clinical entity, often presenting diagnostic challenges due to its nonspecific symptoms and resemblance to other thyroid conditions such as malignancies or cystic lesions. This case highlights the importance of considering thyroid TB in the differential diagnosis of thyroid swellings, especially in endemic regions. Treatment with ATT remains the cornerstone of management, while surgical interventions may be required for abscess drainage or complications.

Introduction

Tuberculosis (TB) was the world’s second leading cause of death from a single infectious agent in 2022. An estimated 10.6 million people fell ill with TB worldwide in 2022. The TB incidence rate is estimated to have increased by 3.9% between 2020 and 2022, with COVID-related service disruptions leading to nearly half a million TB deaths in these 3 years^[1].

HIGHLIGHTS

• Thyroid tuberculosis (TB) is a rare form of extrapulmonary TB, often misdiagnosed due to its nonspecific symptoms.

• Thyroid TB is rare, with an incidence of 0.1–0.4%, possibly due to the thyroid gland’s bactericidal properties and rich blood supply. Treatment primarily involves antitubercular drugs, with surgical drainage required in complex cases.

• Thyroid TB should be considered in thyroid swellings, especially in TB-endemic regions. Imaging and Fine needle aspiration cytology (FNAB) are crucial for diagnosis, while a combination of medication and surgery ensures the best outcomes.

It is frequently misdiagnosed or delayed due to its nonspecific signs and symptoms, which include fever, night sweats, fatigue, single or multiple nodules, goiter with caseation, chronic fibrosing nodules, and cold or acute abscesses^[2].

TB of the thyroid is a rare disease even in an endemic country like Somalia. To establish a diagnosis of thyroid TB is challenging since it can mimic a carcinoma, suppurative abscess or a hemorrhage in a thyroid cyst. In this paper, we present the case of thyroid TB that developed while the patient was on antitubercular therapy. The diagnosis was made on fine-needle aspiration (FNA) of the thyroid gland^[3].

Thyroid TB is uncommon probably due to the anti-bactericidal properties of colloids within the thyroid follicles and high vascularization of the gland^[4].

Diagnosis of thyroid TB is often missed or delayed due to nonspecific signs and symptoms and presents in various clinical manifestations, including single or multifocal nodules, chronic sinuses, goiter with caseation, chronic fibrosing nodules, and cold or acute abscess^[4,5]. In some circumstances, it can mimic thyroid cancer with some mechanical obstruction signs, including hoarseness or dysphagia, as shown in our case. Ultrasonography-guided FNA biopsy is appraised as an important procedure to assist the diagnosis for detailed examination of cytology and acid fast bacilli (AFB) culture^[3,4]. Although antituberculous therapy remains the mainstay of treatment, surgery is still often performed to facilitate abscess drainage and to prevent total destruction of the thyroid tissue^[3,4]. Failure to respond to antituberculous drugs and recurrence occur in around 1% of cases due to multidrug resistance^[4]. Although very rare, atypical presentation of extrapulmonary TB in the thyroid gland requires thorough anamnesis and in-depth examination.

Case presentation

A 14-year-old girl presented with swelling in the right lobe of the thyroid. There were no generalized symptoms like fever, malaise, night sweats, or weight loss. There was no history of difficulty with swelling or voice change. No known TB contact or past history of TB in the patient or immediate family.

On clinical examination, there was a single abscess of size 6 × 4 cm in the right lobe of the thyroid, moving with swallowing. The smooth surface, non-tender with normal overlying skin. There were no clinical features of hypothyroidism or hyperthyroidism. Routine blood investigations were done; hemoglobin 11.0 g/dl, total leucocyte count 8600/mm³, and neutrophils 67/ mm³. The erythrocyte sedimentation rate was 30 mm. Thyroid function tests, T3, T4, and TSH, were normal. The X-ray chest was normal. Ultrasonography of the neck revealed a 30 × 120 mm encapsulated collection anterior to the thyroid gland. The CECT scan of the neck was done to rule out carcinoma of the thyroid gland. This was helpful in the diagnosis of tubercular thyroid abscess as a localized caseous anterior to the thyroid lobe and figured out the presence of a suprclavicular lymph node.

FNA was done to confirm the diagnosis. The stained smears revealed predominantly sheets of neutrophil, with necrotic dirty granular background, scattered lymphocytes and scattered aggregates of foamy histiocytes and epithelioid granuloma. No malignant cell evident (Fig. 1) and diagnosed as suppurative granulomatous inflammation consistent with TB, GeneXpert test: trace for Mycobacterium tuberculosis nucleic acid material. The patient underwent a minimal incision and drainage procedure; no thyroidectomy was performed (Fig. 2).

Figure 1.

Illustration shows predominantly sheets of neutrophil, with necrotic dirty granular background, scattered lymphocytes.

Figure 2.

Illustration shows intraoperative abscess drainage. Diagnostic method for tuberculosis of the thyroid gland.

The patient was put on antitubercular treatment with four drug regimens. Intensive phase: Four drugs for 3 months.

Continuation phase: Three drugs for 6 months.

Noted that full resolution occurred after this regimen. FNA cytology and GeneXpert results confirmed TB. A CT scan helped differentiate the location and extent of the lesion. This was an isolated thyroid TB with no pulmonary involvement or evidence of miliary spread. Chest X-ray was normal; no respiratory symptoms. Pulmonary TB ruled out.

The swelling decreased in size over the next 3 months. The patient increased in weight and continued on three drug regimens for another 6 months, leading to complete resolution of swelling (Fig. 3).

Figure 3.

Illustration shows a healed wound after 3 weeks post-incision and drainage.

This case report has been reported in line with the SCARE checklist^[6].

Discussion

TB of the thyroid gland is a rare disease with an incidence of about 0.1–0.4%^[7]. This can be based on the resistance of the thyroid gland to infections, which is attributed to a number of factors, as follows: a prosperous lymphatic and vascular supply, a well-developed capsule, high iodine contents of the gland, and the bactericidal effect of the colloid and iodine^[8].

TB of the thyroid gland can be primary or secondary and occurs in association with tuberculous infection of the other tissues or organs^[4]. Frequently, secondary extension is seen due to hematogenous dissemination or direct extension from an active laryngeal or nodal focus^[9].

In thyroid TB, the duration of presenting symptoms varies from 2 weeks to 1 year, and there is no relationship with age or sex^[10]. The most common symptoms are fatigue, fever, night sweats, and weight loss. The pressure symptoms, like dysphagia, dyspnea, and dysphonia, may be present^[11].

In conclusion, TB of the thyroid gland should be kept in mind in patients with non-tender, cold nodules. FNA is a rapid, simple, and effective diagnostic method for TB of the thyroid gland. FNA cytology and gene expert results confirmed TB. A CT scan helps differentiate the location and extent of the lesion. We ruled out pulmonary TB, chest X-ray was normal, no respiratory symptoms, pulmonary TB ruled out.

Once thyroid TB is diagnosed, anti-TB drugs can be given first. Although antituberculous is still the cornerstone of therapy, surgery is frequently used to promote abscess extraction and avoid total thyroid tissue degradation^[4,5]. About 1% of cases fail to respond to antituberculous drugs and relapse because of resistance to multiple drugs. Although extremely uncommon, atypical manifestations of extrapulmonary TB in the thyroid necessitate a comprehensive history and examination. Clinicians should be highly suspicious of high-risk individuals who have medical comorbidities, such as immunocompromised diseases, from endemic regions^[1].

Conclusion

Tubercular thyroid abscess is a rare clinical diagnosis, as pulmonary TB may not be associated with pulmonary TB in most of these patients. Tubercular thyroid abscess can be diagnosed only with a very high degree of clinical suspicion. Imaging techniques like magnetic resonance imaging scan and computed tomography scan are useful in making the diagnosis of tubercular thyroid abscess. Definitive diagnosis can be made by cytological examination by the presence of a tubercular granuloma. Tubercular thyroid abscess can be treated by aspiration of pus followed by antitubercular treatment, thus avoiding surgery of thyroid. This case was an isolated thyroid TB with no pulmonary involvement evidence of miliary TB.

Ethical approval

The patient provided informed written consent for publication, and ethical approval was waived as this is a retrospective case report with no identifiers.

Consent

The patient provided informed written consent to publish this case study and accompanying photographs.

Sources of funding

No funding was needed for this case report, except for the amount required if published.

Author contributions

None.

Conflicts of interest disclosure

All the authors report no relevant conflicts of interest.

Guarantor

Dr Abdihakim Elmi Abdishakur.

Research registration unique identifying number (UIN)

Not applicable.

Provenance and peer review

Not applicable.

Acknowledgements

Not applicable.