Mesoblastic Nephroma - Symptoms, Types, Differential Diagnoses, and Treatment

Introduction:

Mesoblastic nephroma is a type of kidney tumor that is either diagnosed before the birth of a child or during its first few months of life. This tumor is one of the common types of kidney tumors that affect newborns. Most of these tumors are not aggressive and show a better prognosis after treatment. Also, the survival rate of a person suffering from mesoblastic nephroma for approximately five years is about 96 percent. However, few cases have shown instances where mesoblastic nephroma has changed into a malignant tumor that spreads to other neighboring parts of the body. Therefore, this article talks in detail about mesoblastic nephroma that affects newborns.

What Exactly Is Mesoblastic Nephroma?

Mesoblastic nephroma, or congenital mesoblastic nephroma, is a type of kidney tumor that occurs prenatally (before birth) or during the first few months of birth. About three to ten percent of neonatal tumors are mesoblastic nephroma. This tumor was first named in 1967 and was earlier called by other names, such as fetal renal hamartoma or leiomyomatous renal hamartoma. Mostly, this tumor is diagnosed and treated within the first year of life. Several different types of tumors can affect a newborn, and this tumor is one among those.

What Are the Other Common Names With Which Mesoblastic Nephroma Is Denoted?

As said earlier, the name mesoblastic nephroma was framed in the year 1967 by Bolande et al. and is called by some of the other following names:

• Congenital Wilms tumor.

• Congenital mesoblastic nephroma (CMN).

• Boland’s tumor.

• Fetal renal hamartoma.

What Are the Signs and Symptoms Associated With Mesoblastic Nephroma?

Mesoblastic nephroma is commonly diagnosed within a few months after birth or can be diagnosed prenatally. This tumor shows slight male predominance. Some of the common presentations of mesoblastic nephroma are as follows:

• The typical sign of mesoblastic nephroma is the presence of an abdominal mass that could be palpated after birth or can be diagnosed within a few years of life. Usually, this tumor is seen as a necrotic mass in the abdomen and is not presented with any symptoms.

• Increased kidney serum production, associated with hypertension, might be evident.

• Occasional hematuria (blood in urine) can be evident.

• Excess amniotic fluid in the amniotic sac before birth (polyhydramnios).

• Hypercalcemia (increased levels of calcium).

What Are the Other Subtypes of Mesoblastic Nephroma?

The two main subtypes of mesoblastic nephroma are:

• Classic Mesoblastic Nephroma: This mesoblastic nephroma is uncommon and comprises less than one-third of the cases.

• Cellular Mesoblastic Nephroma: This subtype is more common than the other type and usually presents later, after three months of life. The other type can be diagnosed prenatally or immediately after birth. This subtype is aggressive and may cause metastasis.

How to Diagnose Mesoblastic Nephroma?

Following are some of the diagnostic methods to confirm mesoblastic nephroma:

• Mesoblastic nephroma is mostly diagnosed during the prenatal period during the 18th to 20th gestational (inside the womb) week through a detailed fetal anatomy scan.

• An ultrasound can easily diagnose the presence of a mass.

• MRI (magnetic resonance imaging) can help diagnose the masses and help diagnose the origin of masses, which could never be possible with ultrasound scans.

• Ultrasound scanning can also help diagnose abdominal masses after the birth of a child.

• CT (computed tomography) can help with the diagnosis. However, they are not the most favorable diagnosis mode as they involve exposing a newborn to a high dosage of ionizing radiation and intravenous contrast administrations, which might cause adverse effects on the newborn.

• The definite diagnosis, however, can be done only by histologic examination.

What Are Some of the Differential Diagnoses of Mesoblastic Nephroma?

Few other tumors and conditions mimic mesoblastic nephroma, and some of them are as follows:

• Wilms tumor (ultrasound shows similar features to mesoblastic nephroma).

• Rhabdoid tumor (an aggressive pediatric soft tissue sarcoma of the liver, kidney, peripheral nerves, and all the soft parts of the body).

• Beckwith-Wiedemann syndrome (growth disorder).

• Autosomal recessive polycystic kidney disease (a rare genetic disorder affecting children).

• Multicystic dysplastic kidney (a condition in which one of the baby’s two kidneys does not develop normally when the baby is inside the womb).

• Retroperitoneal teratoma (rare undetectable tumors that are nonsymptomatic and get visible only when they become large).

How to Treat Mesoblastic Nephroma?

Following are the treatment measures exercised widely to cure mesoblastic nephroma among newborns.

• Early diagnosis and appropriate treatments show an excellent prognosis and can prevent the metastasis of the tumor.

• Complete surgical removal of the tumor along with the perirenal fat is done. This can reduce the rate of recurrence.

• About four percent of the patients suffer relapses after surgical treatments and about 94 percent of the patients show survival rates after treatments.

• The recurrent tumors are treated surgically followed by radiation and chemotherapy.

• Among everyone affected, the kids diagnosed after three months of age with mesoblastic nephroma, or if the tumor has already metastasized to the renal lymph nodes show a higher recurrence rate and might need other therapies as treatment.

• Studies show that ALK (anaplastic lymphoma kinase) inhibitors, Crizotinib or tyrosine kinase inhibitors, surgical treatments, radiation, and chemotherapy can help in a better prognosis.

• However, the action and success of these drugs depend upon the malignancy rate of the tumor.

What Are the Complications of Mesoblastic Nephroma?

The complications associated with mesoblastic nephroma include:

• Fetal Hydrops - Accumulating a large amount of fluid in the fetal body and tissues causing edema or excessive swelling.

• Respiratory Distress - Collection of fluid in the air sacs of the lungs.

• Shoulder Dystocia at Birth - It is a mechanical problem in vaginal deliveries, which is either characterized by the requirement of additional delivery maneuvers to deliver the baby safely or failure to deliver the baby through downward traction.

• Stillbirths.

• Circulatory problems.

Conclusion:

The news of babies being born with congenital tumors like mesoblastic nephroma that could snatch the lives of these innocent beings before they even begin their lives can devastate the peace of the parents and family members. However, it is important to remember that the medical field has grown vastly and has now developed many treatment modalities that could help cure this tumor. The great news is those appropriate treatments and a proper follow-up after surgery can help the baby live a normal and long life.