An Uncustomary Branchial Cleft Cyst Presentation With Associated Autoimmune Thyroiditis

Area of Science:

• Endocrinology
• Surgical Pathology
• Embryology

Background:

• Branchial cleft cysts are congenital anomalies typically found in the neck's lateral aspect.
• Intrathyroidal branchial cleft cysts are exceptionally rare, with few documented cases.

Observation:

• A 42-year-old female presented with an anterior neck mass and elevated thyroid antibodies.
• Initial fine needle aspiration suggested an epidermal inclusion cyst, but radiology indicated a fourth branchial cleft cyst.
• Histopathology confirmed an intrathyroidal branchial cleft cyst with autoimmune thyroiditis.

Findings:

• The study highlights a rare instance of a branchial cleft cyst within the thyroid gland.
• Histopathology revealed co-existing autoimmune thyroiditis and degenerative changes within the cyst.
• Diagnostic discrepancies arose from initial fine needle aspiration compared to radiological findings.

Implications:

• Emphasizes the importance of multi-site fine needle aspiration for heterogeneous thyroid lesions.
• Radiological correlation is crucial for accurate diagnosis of rare intrathyroidal masses.
• Highlights the need for considering embryogenic anomalies in thyroid pathology evaluations.