# Primary tuberculosis of the thyroid gland complicated with abscess: Case report

## TL;DR

A rare case of primary tuberculosis in the thyroid gland was diagnosed and successfully treated with anti-TB drugs after being initially mistaken for cancer.

## Contribution

This case report highlights the importance of considering primary thyroid TB in differential diagnosis to avoid misdiagnosis and ensure timely treatment.

## Key findings

- Primary thyroid TB is extremely rare and often mimics thyroid cancer, leading to delayed diagnosis.
- FNAC and biopsy confirmed TB by showing granulomatous inflammation and Mycobacterium tuberculosis.
- Prompt anti-TB treatment led to full recovery in the patient after six months.

## Abstract

Tuberculosis (TB), caused by Mycobacterium tuberculosis, mainly affects the lungs and lymph nodes but rarely involves the thyroid. Thyroid TB is usually secondary to infection elsewhere, while primary thyroid TB, where the thyroid is the initial site, is extremely rare and more common in patients with preexisting thyroid disease. Its nonspecific presentation often delays diagnosis and treatment. This case highlights the need for a high index of suspicion for early detection and management.

A 40-year-old female farmer presented with a 20-year history of anterior neck swelling, which increased in size over two months. She developed pain, bilateral cervical lymphadenopathy, and low-grade fever. Examination revealed a sinus tract with purulent discharge from the right thyroid lobe and multiple cervical lymph nodes. Ultrasound suggested thyroid TB; CT scan suggested thyroid cancer with nodal metastasis. Fine needle aspiration cytology confirmed TB. Right thyroid lobectomy with left subtotal thyroidectomy was performed, and histopathology confirmed thyroid tuberculosis. She was treated with first-line anti-TB medications and followed for six months, showing full improvement.

Primary thyroid TB is exceptionally rare and can mimic malignancy. FNAC and biopsy can confirm TB by demonstrating granulomatous inflammation with caseation and identifying Mycobacterium tuberculosis. Clinicians should consider TB in thyroid lesions, particularly in endemic areas, to ensure timely diagnosis and appropriate treatment.

•Tuberculosis (TB) is a contagious infection affecting lungs and lymph nodes; thyroid involvement is rare.•Primary thyroid TB is an unusual presentation, often leading to delayed diagnosis and treatment.•Thyroid TB is often mistaken for cancer or other disorders; definitive diagnosis needs FNAC or biopsy.•Early recognition and prompt management are critical to improving outcomes in such atypical cases.

Tuberculosis (TB) is a contagious infection affecting lungs and lymph nodes; thyroid involvement is rare.

Primary thyroid TB is an unusual presentation, often leading to delayed diagnosis and treatment.

Thyroid TB is often mistaken for cancer or other disorders; definitive diagnosis needs FNAC or biopsy.

Early recognition and prompt management are critical to improving outcomes in such atypical cases.