Objective: To draw attention to some hitherto unnoticed clinicopathological aspects of primary hyperparathyroidism in patients who develop hypercalcaemic crisis.
Design: Retrospective review of records and histopathological archive material.
Setting: University hospital.
Subjects: 54 patients treated for primary hyperparathyroidism with hypercalcaemic crisis between 1961 and 1988.
Main outcome measures: Correlation of age, serum calcium concentration, histopathological appearance and size of tumours associated with hypercalcaemic crisis.
Results: 11/54 (20%) of the patients with hypercalcaemic crisis were younger than 40 years of age. Among 460 patients treated at the same hospital for primary hyperparathyroidism without hypercalcaemic crisis, 23 (5%) belonged to the same age category (p less than 0.001). There was no difference between the two groups of patients regarding histopathological characteristics, with the exception of mitotic activity which was remarkably high in some benign lesions causing hypercalcaemic crisis. The correlation between tumour size and degree of hypercalcaemia was poor, and one-third of the adenomas did not exceed 2 cm in diameter.
Conclusions: Young age is a risk factor regarding the development of hypercalcaemic crisis in primary hyperparathyroidism; the proportions of the pathological entities causing hypercalcaemic crisis do not differ markedly from other cases of primary hyperparathyroidism; the correlation between adenoma size and degree of hypercalcaemia is poor; oxyphil adenomas are as likely to be associated with hypercalcaemic crisis as other types of parathyroid adenoma; and some benign parathyroid lesions associated with hypercalcaemic crisis (hyperplastic glands as well as adenomas) show high mitotic activity.