Endocrine Abstracts

Paraganglioma (PGL) are rare neuroendocrine tumors with an estimated prevalence of 1:6500, with cardiac PGL being even rarer. Although most PGL are benign, approximately 15–35% of PGLs have metastatic disease, with few effective treatment options. Novel therapeutic indications, such as 177Lu-DOTA-TATE for patients with PGL, has been investigated in several clinical trials. A 66-year-old woman was referred to Cardiology in 2011 due to an incidentaloma adjacent to the right atrium on a transthoracic echocardiogram, requested due to arterial hypertension. She underwent excision of the lesion, histology was compatible with paraganglioma, with no evidence of illness until 2021, when she began experiencing anterior chest pain, night sweats and fatigue. CT showed 2 suspicious nodules adjacent to the right superior vena cava (SVC) and a lesion causing extensive bone destruction of the right ischiopubic branch. All lesions show intense MIBG uptake. Analytically, increase (greater than 3× the upper limit) in norepinephrine, dopamine and normetanephrine in 24-hour urine and norepinephrine, dopamine and normetanephrine in plasma. A catecholamine-producing paraganglioma with bone metastasis was identified. Was referred to Endocrinology. Clinically with paroxysms of palpitations, sweating and high blood pressure and weight loss (6 kg in 1 month). She was subjected to alpha blocking. In 68Ga-DOTANOC PET, high-capture lesions: cervical in the carotid space on the right (SUV max 5.2), two mediastinal lesions adjacent to the right SVC (SUV max 89.5), bony in D3 (SUV max 133.7), L1 (SUV max 90.9), right ischiopubic branch (SUV max 118.8) and left pubic symphysis (SUV max 172.8). The genetic study revealed a pathogenic mutation in the SDHD gene. The patient was assumed to have no status for mediastinal surgery and underwent radiotherapy directed at the bone lesions (total dose of 30 Gy), with subsequent slow progression of all lesions, deciding to start therapy with 177Lu-DOTATATE. To date, she has undergone 4 PRRT therapies (total activity 800 mCi) with global clinical and imaging improvement, documented through both CT and PET. We report a rare silent paraganglioma adjacent to the right atrium. Having subsequently become productive and metastasized, leaving us with few treatment options. She responded well to PRRT, which went against the odds. The management of PGL is challenging due to the uncertain behavior during long-term follow-up, as demonstrated by our case.