pyramidal lobe
A normal variant of thyroid anatomy representing a remnant of the thyroglossal duct. Extends superiorly from the thyroid isthmus.
Full Definition
The pyramidal lobe is a normal anatomical variant present in approximately 50% of individuals, representing a persistent remnant of the embryonic thyroglossal duct. It extends superiorly from the thyroid isthmus toward the hyoid bone and may reach as high as the thyroid cartilage. The pyramidal lobe contains functional thyroid tissue and can be a source of recurrent hyperthyroidism if not removed during thyroidectomy for Graves' disease. During surgery, the pyramidal lobe may be attached to the hyoid bone by fibrous tissue called the levator glandulae thyroideae. Recognition and appropriate management of the pyramidal lobe is important for complete thyroidectomy.
Usage
Usage note: Always document presence or absence of pyramidal lobe in thyroidectomy reports.
In Context
- "A prominent pyramidal lobe extending to the hyoid bone was identified and removed." — Operative report
- "The pyramidal lobe was carefully dissected to ensure complete thyroid tissue removal." — Surgical note