Calcospherites in pituitary prolactinomas. A hypothesis for their formation.

Calcospherites are being reported with increasing frequency in pituitary prolactinomas. Ultrastructural study of such a case, along with the recent characterization of the molecular composition of prolactin granules, has led us to hypothesize that a unique intracellular milieu exists in which calcification can be initiated and can proceed to calcospherite formation.