Lymphocytic infiltration and destruction of parathyroid adenomas: a possible tumour-specific autoimmune reaction in two cases of primary hyperparathyroidism.

Two cases of primary hyperparathyroidism with underlying parathyroid adenomas were found to be associated with lymphocytic infiltration and destruction of the neoplastic tissue. There was no inflammatory infiltrate in the adjacent rim of the remnant of parathyroid gland or in the other tumour-free glands. The lymphoid cell population within the tumours was composed of both infiltrating T-cells and compact nodule-forming B-cells. In one of the tumours there was considerable fibrosis and atrophy of the adenomatous tissue. The histological picture was consistent with an autoimmune process directed against the adenomas, indicating that this reaction had, in part, been successful in reducing the abnormal cell population.