Intrathyroid cysts of thyroglossal duct origin

Area of Science:

• Endocrinology
• Surgical Pathology
• Head and Neck Surgery

Background:

• Thyroglossal duct cysts (TDCs) typically arise along the thyroglossal duct's path from the tongue base to the manubrium.
• Intrathyroidal TDCs are rare presentations, often discovered incidentally or as cystic thyroid nodules.

Observation:

• Two cases of intrathyroidal TDCs presenting as cystic thyroid nodules are described.
• Fine-needle aspiration biopsy revealed benign squamous cells in both patients.
• Surgical exploration identified cysts within the thyroid isthmus and right lobe, confirmed pathologically as TDC.

Findings:

• Pathologic analysis confirmed the cysts were lined by squamous epithelium, consistent with TDCs.
• The cysts were entirely within normal thyroid parenchyma, without connection to the thyroglossal duct tract.
• Both patients underwent successful surgical resection (thyroid lobectomy/isthmusectomy) with no recurrence.

Implications:

• Intrathyroidal TDCs should be considered in the differential diagnosis of cystic thyroid lesions.
• Fine-needle aspiration biopsy is crucial for diagnosis and can detect associated occult carcinomas.
• Surgical resection is curative; a Sistrunk procedure may be indicated if a residual tract is identified.