Primary lymphangioma of the thyroid gland.

A 21-year-old woman presented with a solitary, hypofunctioning right thyroid nodule. Findings of fine-needle aspiration biopsy were consistent with a thyroid cyst, but a subsequent biopsy demonstrated changes suggestive of a papillary neoplasm. Surgery was performed and a well-circumscribed 12-mm nodule was identified within the thyroid parenchyma. Microscopic examination confirmed the presence of a thyroid lymphangioma. To our knowledge, this is the first case of a primary thyroid lymphangioma reported in the English literature.