Background: Foregut cysts represent abnormal budding of the tracheobronchial anlage during embryogenesis. They occur most commonly in the mediastinum and pulmonary parenchyma and very seldom in the neck.
Case: A 42-year-old woman developed neck swelling and discomfort. An ultrasound scan showed a cystic nodule with a thick wall extending from the left lower pole of the thyroid gland. The material obtained from fine needle aspiration of the cyst demonstrated numerous detached ciliated tufts (DCTs) in a background of amorphous debris and degenerated cells. A diagnosis of ciliated cell remnants or DCTs consistent with a foregut cyst was made.
Conclusion: Although this entity is rare, awareness of its occurrence in the thyroid gland may prevent unnecessary surgery.