Lymphocytic infiltrates in solitary parathyroid adenomas - A report of four cases with review of the literature

We describe four cases of solitary parathyroid adenomas with prominent lymphocytic infiltrates presenting as primary hyperparathyroidism. There was no involvement of the other parathyroid glands in the three cases in which they were biopsied. In two cases the thyroids were removed and were without lymphoid infiltrates. The infiltrates were composed of a mixed population of B and T lymphocytes in the three cases that had material available for immunohistochemistry. There was no evidence of parathyroid parenchymal destruction, and in none of the patients was an autoimmune disease present clinically or serologically. We hypothesize that lymphocytic infiltrates in parathyroid adenomas are an uncommon, but clinically innocuous, histologic finding and their presence does not imply an autoimmune disorder.