CASE OF THE MONTH

 

PRESENTED BY

THE THYROID SURGERY CENTER OF TEXAS, P.A.

1927 Lohmans Crossing Road, Suite 201, Austin, TX 78734

www.thyroidcancer.com

512-608-9595; Fax-512-608-9833

 

THE IMPORTANCE OF THE PYRAMIDAL LOBE

 

Almost all lay people, and many doctors, think of the thyroid gland as an organ made up of two lobes. Sometimes I even receive a radiology report talking about the “left” thyroid and the “right” thyroid. Fact is, there are 4 components of the thyroid gland, the right and left lobes, the isthmus that crosses the windpipe and joins those lobes, and the pyramidal lobe, a superior extension of variable length that comes up from the isthmus. The pyramidal lobe is actually a vestigial remnant of the thyroglossal tract. Recall that the thyroid gland embryologically descends in the midline from the foramen caecum at the base of the tongue down to its final resting place low in the anterior neck.

The pyramidal lobe is of great importance to the thyroid surgeon for several reasons. First, when performing total thyroidectomy for Graves’ disease, it is crucial to look for, identify, and remove the pyramidal lobe, as this can be a cause of recurrent hyperthyroidism following an incomplete resection of the gland. Second, it can be the site of origin of a thyroid cancer or contain intraglandular metastasis or multifocal disease, especially in cases of Papillary Carcinoma. Next, if left behind in a patient who will require post operative radioactive iodine, its presence will virtually nullify the anticipated benefit of I131 by absorbing most, if not all, of the radioactive material. Finally, this midline structure may harbor the Delphian lymph node, not infrequently the site of metastasis from a cancer in the body of the thyroid gland. This node gets its name from Greek mythology. The Oracle of Delphi, called Pythria, was a Priestess who would answer questions posed to her, never concealing nor revealing the truth. Thus, an enlarged Delphian node may, or may not, indicate the presence of thyroid cancer.

In the case presented here, this is a Graves’ disease gland, with an extension of pyramidal lobe that went all the way up to the base of tongue. The Delphian lymph node is seen here. In Graves’ disease, there are always enlarged benign lymph nodes in the area around the thyroid, especially in the paratracheal area on both sides. This patient battled her hyperthyroidism medically for many years. Now, after a 50 minute out patient procedure, she is euthyroid, happy, and there is no chance of recurrent disease.

“…Thyroid surgery…it’s all we do…”