Thyroid & parathyroid
Parathyroid nonmalignant
Parathyroid gland hyperplasia
Author: Monika Roychowdhury, M.D.
Last author update: 1 January 2013
Last staff update: 16 December 2024 (update in progress)
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Parathyroid gland hyperplasia[TIAB]
Table of Contents
Definition / general | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics description | Differential diagnosisCite this page: Roychowdhury M. Parathyroid gland hyperplasia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parathyroidpthhyper.html. Accessed December 20th, 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
- Bilateral primary chief cell hyperplasia associated with loss of APC gene (Am J Surg Pathol 2002;26:103)
Treatment
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
Water clear 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
