Parathyroid gland
General
Anatomy and histology

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 11 April 2018, last major update January 2013

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: (Anatomy[TI] OR histology[TI]) parathyroid[TI]

Cite this page: Roychowdhury, M. Anatomy and histology. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/parathyroidanatomy.html. Accessed July 21st, 2018.
Definition / general
  • 4 glands in 2 pairs usually close to upper and lower poles of thyroid lobe
  • Discovered in 1880 by Ivar Sandström, a Swedish medical student (Am J Surg Pathol 1996;20:1123)
  • May be found anywhere along pathway of descent of branchial pouches
  • 10% have 2 - 3 glands; 5% have 5 glands, 0.2% have 6 glands
  • Upper pair arises from fourth branchial cleft and descends with thyroid gland; usually at cricothyroid junction
  • Lower pair arises from third branchial cleft and descends with thymus; usually near inferior thyroid
  • Other locations: carotid sheath, anterior mediastinum, intrathyroidal; glands tend to be bilaterally symmetrical
  • Stromal fat increases to 30% at age 25; percent fat is related to constitutional percent fat but reduced in dying individuals; mean is 17% with wide variation (Hum Pathol 1982;13:717)
Drawings

Images hosted on other servers:

Embryological pathway of parathyroid migration, showing possible locations for lower parathyroid glands

Gross description
  • Yellow-brown, 25 - 40 mg each gland
Microscopic (histologic) description
  • Composed primarily of chief cells and fat with thin fibrous capsule dividing gland into lobules
  • May have a pseudofollicle pattern resembling thyroid follicles (pink material is PAS positive)

Chief cells:
  • 6 - 8 microns, polygonal, central round nuclei, contain granules of parathyroid hormone (PTH)
  • Basic cell type, other cell types are due to differences in physiologic activity
  • 80% of chief cells have intracellular fat
  • Chief cell is most sensitive to changes in ionized calcium

Oxyphil cells:
  • Slightly larger than chief cell (12 microns), acidophilic cytoplasm due to mitochondria
  • No secretory granules
  • First appear at puberty as single cells, then pairs, then nodules at age 40

Water clear cell:
  • Abundant optically clear cytoplasm and sharply defined cell membranes
  • Chief cells with excessive cytoplasmic glycogen
Microscopic (histologic) images

Images hosted on other servers:

Normal parathyroid gland


Chief cells

Oxyphilic nodule

Clear cells

Colloid type material, without oxalate crystals

Positive stains