Pheo in pregnancy

Pheo in pregnancy is very rare. Most people with pheo are diagnosed after they are 40. If they know they have pheo, younger women would have the tumor removed before becoming pregnant. When pheo does occur in pregnancy, it usually is a big surprise and can have serious consequences to the mother and the fetus. Pheo in pregnancy is one of those “cannot afford to miss” diseases. Once suspected, diagnosis and treatment are usually straightforward and the mother and fetus can expect great outcomes.

Pheo in pregnant women is usually subclinical before pregnancy. The metabolic changes during pregnancy and the growing uterus tend to make the tumor more active. In my experience, pheo-induced hypertension usually occurs later in pregnancy but it can occur much earlier. Clinically it is difficult to differentiate between preeclampsia and pheo. My suggestion to obstetricians is to have a low threshold to test pheo. If the blood pressure is hard to control or there are paroxysmal symptoms such as palpitation, sweating, and headache, I would test pheo just not to miss it. In the vast majority of pregnant women, the test results are negative and pheo is ruled out. In those with clearly elevated pheo markers (the markers are usually markedly elevated in pregnancy), abdominal MRI is then done and the pheo is usually in one of the adrenal glands. CT and MIBG scan are contraindicated in pregnancy due to the associated radiation to the fetus. If pheo is diagnosed in the 1st or 2nd trimester (< 24 weeks), the woman is treated with phenoxybenzamine and beta blocker for preoperative preparation and the tumor is resected laparoscopically. If pheo is diagnosed in the 3rd trimester, the woman is still treated with phenoxybenzamine and beta blocker. When fetus is mature enough, Cesarean section is done, followed by tumor resection.

As pheo in pregnancy is a dramatic disease, there are always a few case reports every year, each with a little different flavor in it. The conclusion of most cases is to consider pheo in a pregnant woman with unusual hypertension. The case brought up by reader DJPheo was about a 27-year-old woman. Biochemical diagnosis was very clear but initial abdominal MRI did not identify a tumor. She received a PET/CT scan which localized the tumor. As DJPheo points out, the case raised a few issues. First, it is surprising that the abdominal MRI did not identify the mass (which is sizable at 5.7 x 2.8 x 3.1 cm) adjacent to the spine. Second, what should be done next if the mass is not seen even by experienced radiologist on abdominal MRI? Most would recommend MRI of the pelvis, chest, and neck. Third, if no tumor is seen after MRI of neck and trunk, what should be done next? I would make sure the blood pressure is well controlled and wait until after delivery (probably safer by C-section) for MIBG scan or PET. At any rate, this case should not be construed as evidence supporting PET/CT scan for localizing pheo in pregnancy. Rather the moral is that you need to find a good radiologist to read the MRI images.

Dr. Pheo