Multiple branchial cleft-like cysts in Hashimoto's thyroiditis.

Area of Science:

• Endocrinology
• Pathology
• Surgical Pathology

Background:

• Hashimoto's thyroiditis is a common autoimmune disease affecting the thyroid gland.
• Intrathyroidal cysts are uncommon and can arise from various causes.
• Branchial cleft cysts are typically found in the lateral neck, not within the thyroid.

Observation:

• Two women with Hashimoto's thyroiditis presented with multiple intrathyroidal cysts.
• Histological examination revealed cysts lined by squamous and focal columnar epithelium.
• The cysts were surrounded by lymphoid tissue characteristic of Hashimoto's thyroiditis and a fibrous capsule.

Findings:

• The described intrathyroidal cysts exhibited unique histological features, distinct from previously reported thyroid cysts.
• Morphologically, the cysts resembled branchial cleft cysts found in the neck.
• The histogenesis remains uncertain, but a derivation from developmental rests is proposed.

Implications:

• These findings suggest a potential association between developmental rests, intrathyroidal cyst formation, and Hashimoto's thyroiditis.
• Further research is needed to elucidate the exact histogenesis and the relationship between these cysts and autoimmune thyroid disease.
• Recognition of these distinct intrathyroidal cysts is important for accurate diagnosis and management in patients with Hashimoto's thyroiditis.