Parathyroiditis associated with hyperparathyroidism and branchial cysts.

A 57-year-old man had renal stones, and biochemical investigation led to a diagnosis of primary hyperparathyroidism. Surgical exploration revealed bilateral inferior parathyroid enlargement. Both glands were removed; macroscopically, small cysts were seen on cut sections. Histologic examination showed broad bands of fibrosis, lymphoid follicles, and plasma cells that diffusely effaced the parathyroid architecture. Such features--if seen in the thyroid gland--would be reminiscent of an autoimmune process. The cysts were lined by respiratory and squamous epithelia and contained lymphoid follicles in their walls. Less affected areas of the parathyroid tissue were hyperplastic. It is believed that the inflammatory response in the parathyroid glands that is described in this article may be characteristic. It may result from the cysts or their contents or from an autoimmune reaction.