Pheochromocytoma is a disease that exhibits a variety of sympathetic symptoms by secreting catecholamines [1,2]. Most of the tumors in this condition are located in the adrenal medulla, but 10% are found in the sympathetic ganglia. Additionally, 10% of these tumors are extra-adrenal, 10% are bilateral, 10% are familial, and 10% are malignant. Therefore, pheochromocytoma is occasionally referred to as the “10% disease”. The incidence of bilateral pheochromocytoma is increased in familial cases. This incidence is increased to 80% in multiple endocrine neoplasia (MEN) IIA cases . Pheochromocytoma during pregnancy is rare, with less than 300 reported cases [3,4,6-8,11]. Moreover, bilateral pheochromocytoma during pregnancy is even rarer than unilateral pheochromocytoma, with less than 20 cases reported . Hypertension can be found in up to 98% of patients with pheochromocytoma . However, the only symptoms and signs of catecholamine secretion in this case was awareness of right abdominal discomfort. Other sympathetic symptoms and signs were not found in our case, such as palpitations, tachycardia, sweating, seizure disorders, anxiety attacks, chest pain, dyspnea, nausea and vomiting, pallor, and flushing.
The diagnosis in our case was confirmed by measurement of 24-h urinary metanephrine and normetanephrine levels, as previously reported . Measurement of 24-h urinary vanillylmandelic acid or catecholamines is also commonly used to confirm diagnosis of pheochromocytoma [3,5,10]. Urinary levels of catecholamines do not increase during normal pregnancy . Localization of the tumor in this case was successful with magnetic resonance imaging (MRI) and abdominal ultrasonography, as in a previous report . Computed tomography can be used to locate the tumor , but MRI has the advantage of lacking ionizing radiation [3,13]. Therefore, MRI is safe and used in pregnancy. However, iodine 131-metaiodobenzylguanidine scans is often necessary for localization . Iodine 131-metaiodobenzylguanidine is used during the postpartum period . These tests were not used in our case because MRI did not demonstrate extra-adrenal tumors, and postoperatively, the follow-up 24-h urinary metanephrine and normetanephrine levels decreased over time. Alpha-blockade was used as a first line medical treatment in our case, as described previously [3,5,10]. Maternal mortality from pheochromocytoma in pregnancy is high (4–17% or higher) if it is undiagnosed [3,7]. The diagnosis in our case was made in the first trimester, and therefore, maternal mortality did not occur. In a recent series, maternal mortality fell from 4–17% to 0–2% when the diagnosis was made antepartum [3,14].
The main treatment of pheochromocytoma is surgical removal . The timing of the surgery is controversial and requires consideration on an individual basis. Surgery is less preferred during the first trimester because of the higher incidence of miscarriage. Adrenalectomy is recommended for second trimester cases. In the third trimester, surgery is delayed or often performed during cesarean section. In our case, pheochromocytoma was detected in the first trimester, and we continued management of blood pressure. Surgery was performed during pregnancy at 15 weeks’ gestation after waiting for development of the fetus. We waited until this time because enlargement of a gravid uterus makes operating technically difficult during an advanced pregnancy, and delaying the operation may be dangerous for both the mother and the fetus [3,5].
The majority of pheochromocytoma occurs sporadically. As mentioned above, approximately 10% of pheochromocytoma is familial, and it is usually bilateral. When bilateral pheochromocytoma is found, the associated syndromes should be searched for. These syndromes include MEN IIA (Sipple’s syndrome), MEN IIB (mucosal neuroma syndrome), neurofibromatosis, and von Hippel–Lindau disease . However, dysmorphic features, including central obesity and skin striatum, were recognized. Furthermore, laboratory findings did not show these syndromes in our case.