REVIEW OF PEDIATRIC RENAL NEOPLASMS
John Hicks
Texas Children's Hospital, Houston, TX

OSSIFYING TUMOR OF INFANTILE KIDNEY

INDEX

Ossifying Tumor of Infantile Kidney: Epidemiology

Rare Distinctive Tumor of Infantile Kidney
(5 reported cases)

Patients Less Than 4 Months of Age

Presented with Hematuria

Relatively Small Calcified Renal Masses (2 to 3 cm)

Benign Course with Surgical Excision in Most Cases

No Recurrences in Cases Followed for 5 and 10 years

Two Cases Initially Believed to Be Wilms Tumor
Treated with Chemotherapy

Ossifying Tumor of Infantile Kidney: Pathology

Arise in the Calyceal/Pelvic Region of Kidney

Ill-Defined Margins and Extend into Medulla

Sheets of Spindled to Polygonal Cells with Eosinophilic Cytoplasm

Transform into Plump Ovoid Cells with Associated Osteoid and Bone Production

Occasional Typical Mitoses and No Pleomorphism

No Metastatic Disease to Date

Cytogenetics in 1 Case; No abnormalities

Ossifying Tumor of Infantile Kidney: Pathology; Light microscopy (A) and Ultrastructure (B)

Figure 7A:.Transition between plump spindle cells and areas with osteoid production.	Figure 7B: Spindle cell component resembles myofibroblasts with features similar to those for congenital mesoblastic nephroma.

Ossifying Tumor of Infantile Kidney: Histogenesis

Origin of Tumor

Urothelium (Transitional Cell Derivation)

Variant of Congenital Meoblastic Nephroma
(Mesenchymal Derivation)