Introduction
Advancements in imaging technology and the extension of prenatal evaluation have led to a rise in the incidence of fetal malignancies. Prenatal (before birth), maternal (mother-related), and neonatal (newborn) treatment greatly depends on the early identification of a prenatal tumor and the comprehension of its imaging characteristics. Fetal cancers are typically detected and diagnosed by ultrasound; however, magnetic resonance imaging is being utilized more frequently as a supplemental technique.
When compared to tumors in children, many prenatal cancers differ in their clinical and imaging characteristics. Some specific imaging findings may carry early accurate detection of fetal tumors, which may change the prenatal management of pregnancy and the manner of delivery and permit urgent postnatal treatment.
What Are Fetal Tumors?
Tumors that arise from various fetal tissues are known as fetal tumors. Tumors can sometimes cause harm to the fetus by demanding an extensive blood supply. Hydrops (abnormal fluid build-up) and fetal cardiac failure could arise from this. They are a rare and complex category of prenatal abnormalities that range from benign lesions that might cause fatal airway blockage if not treated properly to those with mass effects and low malignant risk to very uncommon fetal cancers.
The true prevalence of congenital tumors may be significantly greater than the stated range of 1.7 to 13.5 per 100,000 live births, as many stillbirth or abortion cases may go unreported. A recent study found a higher frequency of congenital malignancies (present at birth), most likely as a result of improved imaging methods and a more comprehensive prenatal examination.
What Are the Examples of Fetal Tumors?
The most common fetal tumor, sacrococcygeal teratoma, affects around 1 in 40,000 babies born. On ultrasonography, it presents as a solid, complex, or filled with a fluid lesion that extends to varying degrees from the perineal region. The following are some examples of fetal tumors:
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Sacrococcygeal teratoma
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Head and neck teratoma.
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Rhabdomyosarcoma.
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Mediastinal teratoma.
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Intrapericardial teratoma.
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Retroperitoneal teratoma.
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Fetal astrocytoma.
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Fetal choroid plexus papilloma.
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Fetal intracranial lipoma.
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Cardiac rhabdomyoma.
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Cardiac fibroma.
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Cardiac teratoma.
What Are the Signs and Symptoms Associated With Fetal Tumors?
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One significant general indicator of fetal tumors is polyhydramnios (too much amniotic fluid). In severe cases of polyhydramnios, fetal malignancies account for nearly half of cases. In these situations, mechanical blockage (such as GIT tumors), swallowing difficulties, increased fluid generation, and impaired resorption by lung tissue constitute the possible causes of polyhydramnios.
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Up to 50 % of intracranial tumor cases present with polyhydramnios. Pathologic alterations within the tumor mass have a distinct sonographic appearance and are indicators of tumor-specific signals. These consist of fast changes in size and texture, calcifications, organ edema, liquification, internal bleeding, and neovascularization.
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Organ-specific symptoms are uncommon, although some sonographic images, such as cardiomegaly with a massive solid or cystic mass encircling the entire heart, indicating an intrapericardial teratoma may raise strong suspicions that they are related to fetal malignancies.
How Are Fetal Tumors Diagnosed?
Various diagnostic tests may be employed in addition to ultrasound. Imaging methods can involve MRIs (magnetic resonance imaging) and X-rays. Sonography has not yielded any greater information than X-ray approaches. In situations of brain malignancies, thorough sonographic imaging is still preferable, even with brain CT (computed tomography). When an alternative to ultrasound is needed, magnetic resonance imaging is the first option because it is a non-invasive, non-ionizing imaging technique.
However, the use of MRI is restricted to the third trimester since fetal motions in cases of polyhydramnios (as in cases of neoplasm) limit the ability to see both abnormal and normal anatomy. Fetal tumors can occasionally be mistaken for aberrant or normal sonographic results. Examples range from extreme cases of bladder extrophy, in which the bulging bladder mass resembles a solid tumor, to uncommon instances of fetal scrotal inguinal hernia, in which the bowel loops inhabit the scrotum and appear as enormous lumps.
What Is Fetal Tumor Resection?
Fetal tumor resection is done in fetuses with complicated tumor masses. One treatment option for fetal tumors is to cut off their blood supply. Open fetal surgery may be necessary in severe situations. Tumors may occasionally be positioned in a way that compresses the embryonic airways, necessitating the use of an unusual delivery method known as EXIT (ex-utero intrapartum therapy). Following treatment for fetal malignancies, the patients will need continuous access to multidisciplinary care.
What Are the Steps Involved in Fetal Tumor Resection?
Prompt intervention is advised if the fetus with fetal tumors has fetal hydrops and their health puts them at risk. The doctors will do an urgent cesarean delivery if the infant is healthy. Fetal surgery to remove the tumor will be indicated if the baby is not ready for delivery. To completely relieve pain during fetal surgery for tumor resection, the mother will be given general anesthesia. While most of the fetus's pain will be relieved by general anesthetic, the baby will also get extra anesthesia throughout the procedure.
The uterus will be partially removed from the abdomen by the fetal surgeon in an incision similar to a cesarean section. This is referred to as a hysterotomy. The baby's tumor will then be visible to the surgical team after the uterus is opened. The tumor will be removed by the fetal surgeon, who will also repair the baby's wound. After that, the abdominal incision is closed, and the uterus is reinserted into the abdomen. Mothers stay in the hospital for several days to recover after this surgery.
Conclusion
Tumors can arise in any of the fetal organs, even though they are rare during the early stages of pregnancy. Prenatal ultrasound tests have improved the identification and diagnosis of fetal malignancies, and in certain situations, MRI can aid in the differential diagnosis. Understanding the imaging findings and pathophysiological traits of fetal tumors is crucial for the diagnosing physician because they can change how pregnancy is managed prenatally and how it goes during delivery.
