# Hydatid Cyst of Thyroid Gland: A Case Report

## TL;DR

A rare case of a hydatid cyst in the thyroid gland was successfully treated with surgery and diagnosed using fine needle aspiration.

## Contribution

This case report highlights the successful diagnosis and management of a rare thyroid hydatid cyst using fine needle aspiration and lobectomy.

## Key findings

- A 64-year-old male was diagnosed with a hydatid cyst in the thyroid via fine needle aspiration cytology.
- The patient was successfully treated with lobectomy and showed no recurrence after one year.
- FNAC confirmed the diagnosis by identifying hooklets, protoscolices, and laminated membrane.

## Abstract

Hydatid cysts in the thyroid gland are extremely rare, even in endemic areas. A 64‐year‐old male presented with a painless swelling on the left side of the thyroid swelling for 2 years. Ultrasonography revealed a large multiloculated anechoic lesion while fine needle aspiration cytology yielded clear watery to granular fluid containing hooklets, protoscolioces, laminated membrane, identifiable on both Giemsa stained and unstained slides. Further tests confirmed positive serology for Echinococcus, and computed tomography (CT) scan showed no such cysts in other organs. The patient was treated successfully with a lobectomy without signs of recurrence in 1 year. Although primary hydatid cysts of the thyroid are rare, even in endemic areas, they should be considered as a differential diagnosis when evaluating thyroid nodules in these regions. Fine needle aspiration cytology (FNAC) can confirm the diagnosis. However, clinicians must take care to avoid anaphylactic reactions. The use of FNAC in hydatid disease is debatable as it may cause anaphylactic reaction, but in cases with doubtful diagnosis, it can serve as a confirmatory tool. The condition can be managed successfully with lobectomy.