Discussion

Abstract

Orator and Schleussing (1931) observed the postnatal development of the human thyroid gland and noted the following: In the newborn the thyroid glands are solid. The histological development is found to start in the regions of the polar and peripheral zones of the lobe and prevails over the central zone by forming central vesicles (Zentralbläschen) of the lobules in which the colloid has not yet appeared. These central vesicles soon become central colloid vesicles (Zentralkolloidbläschen) to acquire the colloid. This development begins in the second month and persists through the 6th month to the second year. Around the second year the colloid appears also in the solid parenchyma surrounding the central colloid vesicles, and shortly after the diffuse colloid thyroid gland — young colloid type (diffuse Kolloidschilddrüse, Jungkolloidtyp) develops. This type persists from the third to 10 years. Beyond 30 years, the thyroid gland does not proliferate but rather shows decrease in follicle size and colloid content. An earlier observation of the thyroid gland shortly after birth to 29 years old (Orator and Walchshofer, 1927) described a similar developmental pattern: The newborn thyroid gland is solid and the lobule consists exclusively of colloid-free parenchyma surrounding a central slit cavity. The thyroid gland grows, through two stages of central vesicle type (Zentralbläschentyp) and children type (Kindertypus) between two and 9 years, to the adolescent thyroid gland (Jugendschilddrüse) at puberty and the mature thyroid gland (Reife-Schilddrüse) later.