Endocrine Abstracts

Introduction: Mediastinal paragangliomas are rare. These tumours can be associated with increased morbidity and mortality when invasive growth to the heart, great vessels, esophagus and trachea occurs. Surgical resection, if feasible, is the treatment of choice.

Case report: A 50-year-old man presented with severe and refractory left gluteal pain radiating to the posterior thigh for two months. The patient had no relevant medical history and no other symptoms. Computer tomography (CT) was performed and suggested a metastatic osteolytic lesion in the sacrum and left iliac bone (6×5 cm). Chest-CT identified a large mass involving the right atrial appendage and atrium extending from the right ventricular outflow tract to the diaphragm (13×8.7×7.9 cm). This hypervascular lesion showed close proximity with the heart and great vessels without a clear cleavage plan with these structures. An echocardiogram confirmed the presence of an extra-cardiac mass adherent to the heart without affecting myocardial or valvular function. A cardiac magnetic resonance imaging (MRI) with respiratory gating showed extensive cardiac invasion by the mediastinal tumour, excluding the possibility of surgical resection without heart transplant. A guided biopsy of the iliac mass was compatible with metastatic paraganglioma with Ki67 of 40%. The patient was then referred to the endocrinology clinic. Family history was positive for a non-functioning vagal SDHD in a half-brother, who had undergone surgey 10 years before, as well as father’s death with a neck mass. Genetic testing was not performed in proband’s brothers at that time. The same SDHD mutation was confirmed in the patient. Functional imaging study with 68Ga-DOTA-NOC showed intense uptake in the known lesions in the mediastinum and sacrum, and also in the left parapharyngeal space. The patient was recently proposed for chemotherapy with Capecitabine and Temozolamide and supportive cardiac treatment. The iliac-bone lesion was treated with 20 Gray of palliative local radiotherapy (RT) and painkillers, with symptomatic improvement.

Discussion: SDHD mutation is the most frequent familial paraganglioma syndrome and is an imprinted gene, with paragangliomas occurring in patients who inherited the mutation from the father. Genetic counselling and testing of the paternal line may result in earlier diagnosis and treatment of the relatives. Malignant mediastinum paragangliomas associated with heart infiltration and SDHD mutations are extremely rare. Beyond atypical presentation, location and tumor behaviour, this case report highlights the importance of establishing a hereditary syndrome in the proband.