Mesoblastic Nephroma

  • Etiology: Hamartoma of kidney, classification has 3 types:
    — Classic: Non-aggressive, usually solid, no hemorrhagic or cystic or necrotic components
    — Cellular: More aggressive
    — Mixed:
  • Imaging:
    — Predominantly solid but may contain cystic components and therefore can be homogeneous or heterogenous
    — Variable enhancement as solid components may enhance due to nephron entrapment
  • Imaging US: Non-encapsulated large solid renal mass that may be difficult to separate from kidney
  • DDX:
  • Complications: 10% relapse – mostly cellular type
  • Treatment: Surgical
  • Clinical:
    — 5% of all renal tumors
    — Most common renal neoplasm in fetus and children less than 1 year old
    — Presentation Prenatal: Polyhydramnios, hydrops, pulmonary hypoplasia
    — Presentation Postnatal: Incidental mass, hypertension (renin – entrapped renal elements), hypercalcemia (parathormone), respiratory distress

Radiology Cases of Mesoblastic Nephroma

Radiology Cases of Mesoblastic Nephroma Classic Type

US of mesoblastic nephroma
Transverse (above) and sagittal (below) US images shows an enlarged solid reniform shaped mass in the right renal fossa.

Radiology Cases of Mesoblastic Nephroma Cellular Type

CT of mesoblastic nephroma, cellular subtype
Coronal CT with contrast of the abdomen (below) shows a solid mass with variable enhancement with cystic components within the right kidney. Axial CT (above) shows the cystic component of the mass extends to the midline. No claw sign is present. The left kidney is normal.

Surgery Cases of Mesoblastic Nephroma Classic Type

Surgical image of mesoblastic nephroma
Surgical image shows an extremely large right renal tumor displacing the cecum into the left lower quadrant.

Gross Pathology Cases of Mesoblastic Nephroma Classic Type

Gross pathology image of mesoblastic nephroma
Gross pathological image shows a large, round, solid renal mass after resection.
Pathological image of mesoblastic nephroma
Gross pathological image shows a light tan to yellow colored tumor mass situated within the lower pole of the kidney which has a fibrous, whorled cut section reminiscent of a leiomyoma.

Histopathology Cases of Mesoblastic Nephroma Classic Type

Histopathology of mesoblastic nephroma
Histopathological image H&E stained section of a classic histology mesoblastic nephroma shows bundles of bland, spindle shaped cells infiltrating normal renal parenchyma. Glomeruli and tubules are not part of the tumor.