Workshops This Weekend! Join Frank Gaillard, Miranda Siemienowicz and Andrew Dixon at RANZCR 2021 Virtual - free for All-Access Pass holders FIND OUT MORE

Pyramidal lobe of thyroid

Last revised by Dr Yuranga Weerakkody on 30 Jan 2021

The pyramidal lobe of thyroid (also known as Lalouette pyramid 5) is a normal anatomic variant representing a superior sliver of thyroid tissue arising from the thyroid isthmus. It is seen as a third thyroid lobe and is present in 10-30% of the population.

It represents a persistent remnant of the thyroglossal duct. It usually arises from the right or left side of the isthmus extending in a cranial direction; pyramidal lobes arising directly from the midline of the isthmus were rare in a large ultrasound study, accounting for only 2% of the cases 3

It is not uncommon to see it on routine thyroid ultrasound, a study of 416 patients in 2014 found it in 21% 3.

All the pathologies that may be seen in the normal thyroid are also seen in the pyramidal lobe.

A band of fibrous tissue may be present extending superiorly from the pyramidal lobe to the hyoid bone, sometimes with a skeletal muscle component, termed the levator glandulae thyroideae muscle 4.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: diagram
    Drag here to reorder.
  • Case 1
    Drag here to reorder.
  • Case 2: pyramidal lobe on ultrasound
    Drag here to reorder.
  • Case 3: pyramidal lobe on I-123 scan
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Case 5: graves disease with pyramidal lobe
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.