Ultrasound and MR imaging show a multiseptated cystic right abdominal mass. The mass arises from the right kidney. It is more difficult to appreciate on ultrasound, but on MR the claw sign with contrast enhancement is evident.
Mesoblastic nephroma is an uncommon neoplasm, but is the most common neoplasm of the kidney in a young infant.
Almost all of these patients present at less than 6 months of life, 90% during the first year.
This is the most frequent benign neoplasm of childhood, comprising 3-10% of renal tumors.
There are classic and cellular varieties, which can occur in the same mass.
Patients usually present with a large abdominal mass, and may even present with in utero ultrasound.
Lesions are usually solid, but can have cystic/necrotic or hemorrhagic components.
Primary radical surgery is usually curative, with 100% of classic varieties showing cure and 85% of cellular varieties showing cure with surgery.
Metastases to the brain, bone and lungs have been reported.
Although neonatal Wilm’s tumor would be possible, it is much more rare than mesoblastic nephroma.
Take Home Messages:
Most common renal neoplasm in the first year of life- Mesoblastic Nephroma.
Renal tumor in Sickle cell trait- Renal Medullary Carcinoma.
Renal tumor with scar- Oncocytoma