Mesoblastic nephroma

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Mesoblastic nephroma is a rare renal tumor that primarily affects infants and newborns. It is also known as congenital mesoblastic nephroma (CMN) and is the most common renal tumor in this age group.

Classification

Mesoblastic nephroma is classified into two main types:

• Classic mesoblastic nephroma: This type is characterized by spindle-shaped cells and resembles fibromatosis.
• Cellular mesoblastic nephroma: This type is more aggressive and has a higher potential for recurrence. It is characterized by densely packed cells and can resemble Wilms' tumor.

Epidemiology

Mesoblastic nephroma is most commonly diagnosed in the first three months of life. It accounts for approximately 3-10% of all pediatric renal tumors. There is no significant gender predilection.

Pathophysiology

The exact cause of mesoblastic nephroma is not well understood. It is believed to arise from abnormal development of the metanephric blastema, which is the embryonic precursor to the kidney.

Clinical Presentation

Infants with mesoblastic nephroma typically present with an abdominal mass that is often discovered incidentally. Other symptoms may include hematuria, hypertension, and polyhydramnios in the prenatal period.

Diagnosis

The diagnosis of mesoblastic nephroma is usually made through a combination of imaging studies and histopathological examination. Ultrasound is often the first imaging modality used, followed by CT scan or MRI for further evaluation. A definitive diagnosis is made through a biopsy or surgical resection of the tumor.

Treatment

The primary treatment for mesoblastic nephroma is surgical resection. The prognosis is generally excellent for the classic type, with a high cure rate following complete removal of the tumor. The cellular type may require additional treatment, such as chemotherapy, due to its higher risk of recurrence.

Prognosis

The prognosis for infants with mesoblastic nephroma is generally favorable, especially for the classic type. The cellular type has a higher risk of recurrence and may require closer follow-up and additional treatment.

See also

• Wilms' tumor
• Renal cell carcinoma
• Pediatric oncology