Pyramidal lobe of thyroid

The pyramidal lobe of thyroid 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, termed the levator glandulae thyroideae. Very occasionally this band may contain skeletal muscle, in which it is termed musculus levator glandulae thyroideae. Very rarely this muscular slip may arise from the thyroid isthmus in the absence of a pyramidal lobe 4.

Anatomy: Head and neck
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Article information

rID: 36922
System: Head & Neck
Section: Anatomy
Tag: variant
Synonyms or Alternate Spellings:
  • levator glandulae thyroideae
  • musculus levator glandulae thyroideae
  • Pyramidal lobe of the thyroid gland
  • Pyramidal lobe of the thyroid
  • Pyramidal lobe of thyroid gland

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Cases and figures

  • Figure 1: diagram
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  • Case 1
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  • Case 2: pyramidal lobe on ultrasound
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  • Pyramidal lobe on I 123 scan
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