Adenoma paratiroideo ectópico asociado a teratoma maduro mediastinal: Una presentación poco frecuente. Reporte de caso

Introduction. Primary hyperparathyroidism is frequently caused by a parathyroid adenoma, which may be located in a typical site or an ectopic one, such as the anterior mediastinum. Mature teratomas are germ cell tumors that can develop in the mediastinum. Although both parathyroid adenomas and teratomas can give rise to mediastinal masses, the coexistence of these two entities in this anatomical region is rare, and no reports were found in the literature during the review of the subject. Clinical case. A 42-year-old woman with symptoms and laboratory findings suggestive of primary hyperparathyroidism underwent a partial parathyroidectomy. During follow-up, laboratory results showed persistent primary hyperparathyroidism while other studies were negative; consequently, an 18F-fluorocholine PET/CT scan was ordered, which identified ectopic parathyroid tissue in the mediastinum associated with a separate mass. Results. Thoracoscopic surgery was performed to resect both lesions. Histopathological examination identified a mature teratoma, with no evidence of parathyroid tissue. Subsequently, the patient’s hormone levels normalized, and she was discharged. Conclusions. The coexistence of an ectopic parathyroid adenoma and a mature teratoma in the mediastinum is an exceptional finding. This case highlights the importance of considering differential diagnoses for mediastinal masses, emphasizing the value of diagnostic aids and a multidisciplinary approach to management.