Parathyroid Adenoma

The parathyroid glands were first identified in animals in the mid-1880s. Felix Mandl performed the first parathyroidectomy in Vienna in 1925. Since then, there have been many advances in the understanding, diagnosis, and treatment of parathyroid disease. The parathyroid glands are small, oval-shaped structures found close to the thyroid. Eighty-five percent of patients have 4 glands, with 2 lying superior and 2 inferior. The superior glands (developed from the fourth branchial pouch) are usually located on the posterior-lateral surface of the middle to superior thyroid lobe. The inferior glands are more variable in location due to their embryological descent with the thymus (both developing from the third branchial pouch) and can be found at any point along its path of descent. Most commonly, they are located in the inferior third of the thyroid gland. A normal parathyroid gland is the size of an apple seed and weighs approximately 0.5 g. Microadenomas are defined as tumors that weigh less than 0.1 g, while a giant adenoma is over 2 g. The average weight of an adenoma is 1 g.
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