Amyloid in normal and pathological parathyroid glands.

Two groups of parathyroid glands have been examined for intrafollicular amyloid. In glands removed surgically it was found in nine cases (16%); in glands removed at necropsy it was found in 23 cases (46%). Also, two postmortem cases of systemic amyloidosis showed involvement of parathyroid glands with an entirely different distribution of amyloid. Compared with other amyloids the tinctorial properties of the intrafollicular amyloid were uniform in reactions with Congo red and Thioflavin T, but the intensity of the staining reaction for amino acids tryptophan and tyrosine was not constant for the follicle amyloid. This variation may be a feature of a maturation process but the derivation of this amyloid remains uncertain.