Angiomyolipoma and Pregnancy
Dr. Alex Shteynshlyuger is a board-certified urologist in NYC. He specializes in the treatment of men and women with kidney cysts, masses, renal cancer and angiomyolipoma (AML).
What is AML?
Angiomyolipoma (AML) is a benign, non-cancerous tumor that is most commonly found in the kidney but may also be found in other organs. While angiomyolipomas are not very common with an estimated prevalence of about 1 in 1000, it is fairly often seen by radiologists on CT scans and kidney ultrasounds as well as by urologists.
Angiomyolipomas are sensitive to estrogens and have a tendency to grow in size under the influence of estrogen. As a result, during pregnancy, it is believed that the rate of growth of angiomyolipomas may be higher, but that has not been confirmed conclusively.
Occasionally angiomyolipoma (AML) may rupture during pregnancy. This is also fairly uncommon as angiomyolipoma is uncommon to start with, and larger angiomyolipomas that are at higher risk of bleeding as still less common. With the trend of increasing age at pregnancy, due to delayed childbearing and success of in-vitro fertilization, the prevalence of angiomyolipoma during pregnancy is likely to have trended up slightly over the years based on our understanding of biology and prevalence of angiomyolipoma in different age groups.
Because angiomyolipoma is so infrequent to start with, a large angiomyolipoma that bleeds is still less frequent, although limited information is available that can be used for prognostic purposes.
However based on population prevalence of angiomyolipoma, the frequency of pregnancy in the same population and the extreme rarity of complications associated with pregnancy and angiomyolipoma, is probably safe to conclude that most women who have small angiomyolipomas have uncomplicated pregnancy and never discover the presence of angiomyolipoma during pregnancy, if ever, given that they are small and asymptomatic.
Angiomyolipomas and Pregnancy: Can it be done?
While we understand that angiomyolipomas have increased the risk of growth during pregnancy, most women with small angiomyolipomas undergo pregnancies without any complications. It is certainly important to monitor angiomyolipoma closely during pregnancy if discovered before or during pregnancy. If the angiomyolipoma is fairly large in size, close or >3 cm, it is probably prudent to treat it if possible electively prior to pregnancy in women of reproductive age who desire to become pregnant.
The challenge is usually what to do about an angiomyolipoma in a pregnant patient that is fairly large, 3-4 cm or greater and which is not bleeding. There is certainly no right answer as each situation is unique with many different considerations including the stage of pregnancy (trimester), symptoms and associated comorbidities, availability of subspecialty services in case of an emergency, and the exact size that need to be taken in the consideration for each woman.