Stage IV Malignant Pheochromocytoma and Pregnancy

Purpose: To report a rare case of induction of labor with stage IV malignant pheochromocytoma. Pheochromocytomas and paragangliomas are rare neuroendocrine tumors of the adrenal medulla and paraganglia, respectively. They secrete catecholamines and can lead to a deadly hypertensive crisis. Routine presentation may include resistant hypertension, persistent headache, sweating, palpitations, and pallor. In the general population, diagnosis is estimated to be 2-8 per every 1,000,000 people. In pregnancy, the occurrence is even more rare and associated with high rates of maternal and fetal mortality, around 50% reported by an early 1971 study. Method: Case Report. Results: A 21-year-old G1P0 female at 39+0 presented for induction of labor. The pregnancy was uncomplicated, except treatment of gonorrhea in third trimester. Past medical history included stage IV pheochromocytoma with metastasis to the right humeral head, secondary to germline SDHB mutation. She underwent resection ten years prior, followed by ten cycles every 21 days of the following chemotherapy: vincristine, cyclophosphamide, dacarbazine. Evidence of metastasis was found in 2020, and she was lost to follow up with no subsequent treatment. She reestablished with oncology during this pregnancy, and the decision was agreed upon to defer restaging/treatment until postpartum. Upon her arrival to the hospital for induction of labor, her vital signs were stable including her blood pressure of 125/77 mm Hg. She denied any complaints and was feeling well. Hematology/Oncology, anesthesiology, and Maternal Fetal medicine were consulted during her inpatient admission prior to delivery. Hematology/Oncology recommended continuation of alpha blockage with prazosin 3 mg twice a day, close monitoring by anesthesia, and to obtain plasma and urine catecholamines and their metabolites. Labor progressed with a cervical ripening balloon, oral misoprostol, oxytocin, and artificial rupture of membranes which revealed meconium-stained fluid. Recurrent late decelerations occurred and risks, benefits, alternatives were discussed regarding continued induction versus operative delivery with known malignant pheochromocytoma. She ultimately had an uncomplicated spontaneous vaginal delivery. Her postpartum course was uncomplicated. Enoxaparin was recommended for her inpatient postpartum stay. Six weeks later, she was seen for an unremarkable postpartum visit without complaints Conclusions: Early diagnosis of pheochromocytoma greatly improves outcomes. Evaluation includes measurements of urinary fractionated metanephrines or plasma free metanephrines, along with the imaging for tumor localization, preferably magnetic resonance imaging (MRI) Once the diagnosis is made, there are four components to managing pheochromocytomas and paragangliomas in pregnancy: surgical resection, alpha-blockade, obstetric care, and genetic testing for hereditary syndromes associated. Surgical resection is optimally timed late first trimester or early second trimester. Alpha-blockage can be achieved by a variety of non-selective or alpha-1 selective medications. Prazosin is a selective alpha-1 adrenergic receptor antagonist which crosses the placenta at about 10-20% that of maternal concentration. Phenoxybenzamine is a non-selective alpha-antagonist that might be preferred for larger tumors and higher catecholamine levels.2 The main concern with phenoxybenzamine is its ability to cross the placenta and cause hypotension and respiratory depression in newborns. It is very important to initiate an alpha-blockade prior to beta-blockade, in order to avoid unopposed alpha-adrenergic vasoconstriction and propagation of a hypertensive crisis. There are a variety of hereditary syndromes associated with pheochromocytomas including the following: RET, SDHB, SDHC, SDHD, SDHA, VHL, TMEM127 and MAX. About 10% are associated with a known hereditary syndrome. Our patient had a known hereditary syndrome associated and plans to notify affected family members.