The Giant Parathyroid Adenoma Reaching Mediastinum: A Case Report

Abstract Background: The primary hyperparathyroidism is the most common disease of parathyroid glands and the third common endocrine disease. Giant parathyroid adenoma is defined as weight > 3.5gr and size of > 2cm, however, the normal weight of the parathyroid gland is about 70mg to 1gr.Case Presentation: This report describes the most giant diagnosed primary parathyroid adenoma due to literature. The case is a 48-year-old Persian man with past medical history of mitral valve replacement and several episodes of bilateral nephrolithiasis. The chief complaints were knee and lower back pain. After complete assessment, the neck mass with possible origin of thyroid were detected and resected by surgery. The size of resected mass was 9×6×4cm weighting 122gr. The histopathological assessment revealed giant parathyroid adenoma.Conclusion: There are some reports of giant parathyroid adenoma describing the weight of up to 110gr leading to significant hypercalcemia with a size of 8cm. despite the size of the giant parathyroid adenomas and parathormone high levels, the calcium crisis may not always occur in these patients and the masses may be misdiagnosed with thyroid mass at primary assessments.