MON-077 - Recurrent Pericardial Effusion as A Masquerading Manifestation of Malignant Bilateral Pheochromocytoma: A Case Report

A diagnosis of bilateral malignant pheochromocytoma is a rare outcome of the workup for recurrent pericardial effusion. Typical symptoms of said neoplasm encompass paroxysmal headaches, palpitations and/or profuse sweating, although presentation in metastatic disease tends to be more insidious in nature. We report a case in which this atypical cardiac manifestation was the sole presenting feature of metastatic pheochromocytoma.

Our patient is 70-year-old woman, former 50-pack-year smoker, with medical history of hypertension, hyperlipidemia, hypothyroidism and left breast ductal carcinoma in situ s/p lumpectomy, radiation and tamoxifen therapy. Family history was notable for multiple malignancies across both the paternal and maternal side. She was noted to have 2 new adrenal masses in the workup for recurrent pericardial effusion in a CT chest. She then underwent a full-body MRI scan, which revealed large bilateral adrenal masses, with radiographic findings suggestive of malignancy. A Cu-64 Dotatate PET/CT demonstrated intense tracer uptake with central necrosis in both adrenal lesions. Additional Dotatate-avid lymphadenopathy was noted in the celiac, portacaval, and pericaval regions, along with a subcentimeter right lower lobe pulmonary nodule showing uptake, consistent with metastatic spread. Biochemical testing revealed markedly elevated total plasma metanephrines at 6585 pg/mL, almost entirely due to normetanephrine (6551 pg/mL). Genetic testing for germinal mutations was negative.

She underwent robotic laparoscopic transabdominal bilateral adrenalectomy, which was uncomplicated. Pathological examination revealed bilateral malignant pheochromocytomas eroding into the adjacent adipose with a satellite growth in the vicinity of the previous stable right adrenal lesion. She was initiated on hydrocortisone replacement therapy for adrenal insufficiency. The patient has scheduled surgery for the removal of abdominal lymph nodes, while further management regarding the pulmonary nodules is still under discussion. Genetic testing showed positive MYCN ( Tier 1 or 2: Strong or potential significance ) NM_005378.5(MYCN):c.131C>T(p.P44L)VAF: 36%

Recurrent pericardial effusion is an exceedingly rare presentation of malignant pheochromocytoma, albeit other cardiac manifestations of this disease are well documented in the literature, such as catecholamine-induced cardiomyopathy and tachyarrhythmias. Genetic testing, especially for known SDHB pathogenic variants, is of vital importance to prompt early detection and screening in family members, given the increased risk for metastatic disease. This case compels physicians to consider malignant pheochromocytoma as a differential, especially in the setting of atypical and recurrent cardiac presentations in patients with prior stable adrenal masses and/or family history of heterogeneous neoplasms.

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