Chief cells (principal cells) are the predominant endocrine cells of the parathyroid gland and are responsible for parathyroid hormone (PTH) secretion. In routine histologic sections, they are classically described as small, uniform, polygonal cells arranged in cords or clusters, closely associated with a rich capillary network.
According to Laiq Hussain (p. 169), their defining morphology is polygonal shape when viewed in histological sections. They characteristically show a central, round nucleus and scant cytoplasm that is often pale to lightly basophilic depending on functional activity and staining.
In contrast to gastric “chief (zymogenic)” cells, parathyroid chief cells do not show a prominent biphasic apical–basal pattern of zymogen granules; instead, they appear as compact endocrine cells with relatively inconspicuous cytoplasmic granularity on light microscopy.
Why the other options are incorrect (Parathyroid context)
No granules ❌
Misleading as an absolute statement. Parathyroid chief cells are secretory endocrine cells and do contain secretory granules (PTH) at the ultrastructural level, even if these granules are not prominently visible like gastric zymogen granules. Therefore, “no granules” is not a dependable description for chief cells.
Darkly staining ❌
Not a consistent feature. Parathyroid chief cells often have pale cytoplasm on routine H&E, and staining intensity can vary with activity. “Darkly staining” is vague and can incorrectly point toward other cell populations.
Basophilic cytoplasm ❌
Only partly true and not the best single descriptor. The cytoplasm is typically scant and pale, and may appear lightly basophilic in some sections. Calling it outright “basophilic cytoplasm” can be an overstatement and is less consistently correct than “polygonal in shape.”
Lobed nuclei ❌
Incorrect. Parathyroid chief cells have round to oval, centrally placed nuclei, not lobulated nuclei. Lobed nuclei are characteristic of certain leukocytes (e.g., neutrophils), not endocrine parenchymal cells of the parathyroid.
