Some cases of primary hyperparathyroidism may not be truly primary in origin.

Primary hyperparathyroidism (PHPT) is the third most common endocrine disorder and is traditionally considered to result from intrinsic pathology. However, this traditional view is challenged by several persistent clinical and epidemiological observations. Therefore, we hypothesize that some cases of PHPT may not be truly primary in origin. Some of them may be irreversible secondary hyperparathyroidism (tertiary hyperparathyroidism), which may be initiated and perpetuated by widely existed chronic calcium and/or vitamin D insufficiency. The "primary" (in fact, irreversible secondary hyperparathyroidism or "tertiary" hyperparathyroidism) and "secondary" hyperparathyroidism states are not dichotomous but are linked through a process of chronic stimulation, adaptive hyperplasia, and eventual clonal transformation. This model is supported by epidemiological evidence demonstrating an association between low lifelong calcium intake and increased PHPT risk, physiological evidence of persistent PTH suppressibility by calcium intake, and the high rate of clinical misdiagnosis between primary and secondary hyperparathyroidism. If validated, this reframing would mandate a paradigm shift in the understanding and management of PHPT or irreversible secondary hyperparathyroidism. It emphasizes the critical need to rigorously identify and correct underlying nutritional deficiency as a fundamental diagnostic and therapeutic step, transforming the management approach from a predominantly surgical model to one focused on prevention, early medical intervention, and addressing a key modifiable environmental cause.