Endocrine Abstracts

Introduction: Primary hyperparathyroidism (PHPT) represents a prevalent medical condition frequently characterized by asymptomatic manifestations. The etiology of PHPT is predominantly attributed to parathyroid adenomas, accounting for 85% of cases, with 10% demonstrating ectopic localization. The prevalence of asymptomatic presentation poses distinctive challenges in both diagnostic and therapeutic realms, necessitating a nuanced approach to effectively address the complexities associated with this pathology.

Observation: In a series of challenging cases, a 54-year-old female patient, previously treated twice for primary hyperparathyroidism (PHPT), underwent left upper parathyroidectomy and mediastinal ectopic parathyroid resection. A decade later, she reappeared with hypercalcemia, elevated PTH, low phosphoremia, and increased 24-hour calciuria. Despite normal ultrasound and cervicothoracic CT results, sestamibi scintigraphy revealed a mediastinal ectopic parathyroid focus. Another case involved a 59-year-old female with primary hyperparathyroidism who underwent parathyroidectomy for a left inferior polar parathyroid lesion. Despite persistent hypercalcemia, elevated PTH, and abnormal 24-hour calciuria, cervical ultrasound and cervicothoracic CT scans showed no abnormalities. However, sestamibi scintigraphy indicated anterior mediastinal ectopy. Additionally, a 68-year-old male patient, post-parathyroidectomy for primary ectopic posterior mediastinal hyperparathyroidism, presented with disrupted phosphocalcic balance. Despite inconclusive results from cervical ultrasound, cervicothoracic CT, and MIBI scintigraphy, a PET scan confirmed posterior mediastinal fixation. In all three cases, thorough investigations for other components of multiple endocrine neoplasia (NEM) yielded negative results, and our patients experienced positive outcomes following surgical resection of the ectopic focus. The anatomopathological study consistently favored the diagnosis of a mediastinal ectopic parathyroid adenoma, highlighting the diagnostic challenges and successful outcomes achieved through advanced imaging-guided interventions in recurrent hyperparathyroidism.

Discussion & Conclusion: The ectopic parathyroid adenoma is a an important cause of refreactory abd recurrent hyperparathyroidism. The mediastinal location of ectopic parathyroid tissue, though relatively rare in contrast to cervical localizations, present distinctive diagnostic and therapeutic challenges. Optimal management entails a meticulous imaging assessment, a pivotal prerequisite for determining precise anatomical localization. This intricate mapping is imperative for devising an exact therapeutic strategy tailored to the unique characteristics of this parathyroid adenoma manifestation.