A Novel Nomenclature to Classify Parathyroid Adenomas

A uniform and reliable description of the exact locations of adenomatous parathyroid glands is necessary for accurate communications between surgeons and other specialists. We developed a nomenclature that provides a precise means of communicating the most frequently encountered parathyroid adenoma locations.

This classification scheme is based on the anatomic detail provided by imaging and can be used in radiology reports, operative records, and pathology reports. It is based on quadrants and anterior-posterior depth relative to the course of the recurrent laryngeal nerve and the thyroid parenchyma. The system uses the letters A-G to describe exact gland locations.

A type A parathyroid gland is a gland that originates from a superior pedicle, lateral to the recurrent laryngeal nerve compressed within the capsule of the thyroid parenchyma. A type B gland is a superior gland that has fallen posteriorly into the tracheoesophageal groove and is in the same cross-sectional plane as the superior portion of the thyroid parenchyma. A type C gland is a gland that has fallen posteriorly into the tracheoesophageal groove and on a cross-sectional view lies at the level of or below the inferior pole of the thyroid gland. A type D gland lies in the midregion of the posterior surface of the thyroid parenchyma, near the junction of the recurrent laryngeal nerve and the inferior thyroid artery or middle thyroidal vein; because of this location, dissection is difficult. A type E gland is an inferior gland close to the inferior pole of the thyroid parenchyma, lying in the lateral plane with the thyroid parenchyma and anterior half of the trachea. A type F gland is an inferior gland that has descended (fallen) into the thyrothymic ligament or superior thymus; it may appear to be “ectopic” or within the superior mediastinum. An anterior-posterior view shows the type F gland to be anterior to the trachea. A type G gland is a rare, truly intrathyroidal parathyroid gland.

A reproducible nomenclature can provide a means of consistent communication about parathyroid adenoma location. If uniformly adopted, it has the potential to reliably communicate exact gland location without lengthy descriptions. This system may be beneficial for surgical planning as well as operative and pathology reporting.