Thyroid & parathyroid

Parathyroid nonmalignant

Parathyroid gland hyperplasia

Last author update: 1 January 2013
Last staff update: 17 August 2023

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PubMed Search: Parathyroid gland hyperplasia[TIAB]

Monika Roychowdhury, M.D.
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Cite this page: Roychowdhury M. Parathyroid gland hyperplasia. website. Accessed February 22nd, 2024.
Definition / general
  • Usually all 4 glands are involved but may be asymmetrical with lower glands being larger
  • Weight of all glands usually 1 - 3 g
  • Usually chief cell hyperplasia, occasionally water clear cell hyperplasia; adipose tissue is rare
  • Some believe adenoma and hyperplasia are different morphologic manifestations of the same process
  • May show clonality

Water clear cell hyperplasia
  • Extreme enlargement of all parathyroid tissue with weights up to 100 g; causes primary hyperparathyroidism
  • Incidence has decreased over past 20 years, now very rare
  • No familial incidence, not associated with MEN (unlike chief cell hyperplasia)
  • Associated with blood group O (Hum Genet 1994;94:195)
Case reports
Primary chief cell hyperplasia
  • Excise 3 of 4 glands
  • Some surgeons remove all parathyroid tissue
  • Can use frozen section, touch prep or intraoperative PTH assay to confirm removal
Gross description
Primary chief cell hyperplasia
  • Classically, all glands enlarged (up to 10 g) vs. pseudoadenomatous (one gland enlarged) vs. occult (all glands normal size but histologically hyperplastic)

Water clear cell hyperplasia
  • Superior glands larger than inferior glands
  • 2 giant glands may appear as one
  • Soft, chocolate brown, with cysts and hemorrhages
  • Pseudopods also common
Gross images

Images hosted on other servers:

3 and a half glands removed

Microscopic (histologic) description
  • Usually no rim of compressed normal tissue
  • May have mitotic activity

Primary chief cell hyperplasia
  • Sheets of chief cells, minimal fat, rare oxyphils
  • Usually no rim of normal tissue

Water clear cell hyperplasia
  • Abundant optically clear cells of variable size (hyperplasia and hypertrophy), with spherical clear vacuoles surrounded by thin eosinophilic material; basal nuclei, compact or alveolar patterns
Microscopic (histologic) images

Images hosted on other servers:

Nodular parathyroid hyperplasia (figures D / E)

Molecular / cytogenetics description
  • Sporadic or part of MEN 1 or 2A

Primary chief cell hyperplasia
  • Increased production of PTH; associated with MEN 1, 2A / 2 in 30% of cases (not MEN 2B / 3)
  • 50% have allelic loss on #11 (where MEN1 gene is located)
Differential diagnosis
  • Adenoma: usually encapsulated, affects one gland with compression of adjacent tissue; most important criterion - no recurrence of hypercalcemia after 5 year followup
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