# Hydatid Cyst Disease of the Thyroid Gland: A Rare Case Report

## TL;DR

A rare case of hydatid cyst in the thyroid gland highlights the need for considering parasitic infections in thyroid nodules, especially in endemic areas.

## Contribution

This case report adds to the limited literature on primary thyroid hydatidosis and emphasizes diagnostic and therapeutic considerations.

## Key findings

- Thyroid hydatidosis is exceptionally rare, with less than 1% of cases.
- Fine needle aspiration is contraindicated, and imaging and serology are crucial for diagnosis.
- Complete surgical excision and albendazole treatment lead to optimal outcomes.

## Abstract

Hydatid cysts caused by Echinococcus granulosus are zoonotic infections endemic to pastoral regions. While hepatic (50 - 70%) and pulmonary (20 - 30%) involvement dominate, primary thyroid hydatidosis is exceptionally rare (< 1% of cases), posing diagnostic and therapeutic challenges. This case underscores the importance of considering parasitic etiologies in thyroid nodules, particularly in endemic zones.

A 26-year-old female patient presented with complaints of pain and swelling in the anteroposterior region of the neck, predominantly on the right side. Fine needle aspiration (FNA) from the nodule seen on ultrasound (US) of the thyroid gland was reported to be suspicious for papillary thyroid carcinoma (PTC), and the patient underwent bilateral total thyroidectomy. In the postoperative histopathological examination, a hydatid cyst was confirmed in the thyroid gland.

Thyroid hydatid cysts, though rare, require high clinical suspicion in endemic regions. Imaging (US/MRI) and serology are pivotal for preoperative diagnosis, while FNA is contraindicated. Complete surgical excision with adjuvant albendazole ensures optimal outcomes. Public health measures, including dog deworming and community education, are critical to disrupting the parasite’s lifecycle.