Ectopic anterior mediastinal parathyroid adenoma: A case report

Primary hyperparathyroidism (PHPT) is characterized by autonomous secretion of parathyroid hormone, resulting in hypercalcemia and systemic complications involving kidney, bone, and neurological functions. It is usually caused by a single benign parathyroid adenoma, with the majority of adenomas located in the cervical region. Ectopic parathyroid adenomas account for up to 5% of cases, most frequently within the mediastinum, posing diagnostic and surgical challenges. We report the case of a 55-year-old male patient who presented with a three-month history of persistent lumbar pain, nephrolithiasis, fatigue, bone and joint pain and severe constipation. Laboratory investigations revealed marked hypercalcemia, hypophosphatemia, hyperparathyroidism and elevated parathyroid hormone (PTH) levels. A non-contrast computed tomography (CT) scan demonstrated an ovoid well-circumscribed soft-tissue density in the prevascular compartment of mediastinum. Subsequently, a technetium-99m-labelled sestamibi parathyroid scan showed a focal area of increased radiotracer uptake was inferior to the thyroid gland, in the prevascular compartment, corresponding to the lesion seen on CT. This finding is characteristic of ectopic parathyroid tissue. The patient underwent successful video-assisted thoracoscopic surgery (VATS) without complications. This case shows the importance of multimodality imaging in the accurate diagnosis and localization of ectopic parathyroid adenomas. Minimally invasive surgical management enables effective treatment with favorable outcomes.