Ossifying renal tumor of infancy

2021-07-07   Rita Alaggio , Paola Dal Cin 

1.IRCCS Ospedale Bambino Gesú , Roma (Italy)
2.Brigham and Women's Hospital , Harvard Medical School, Boston , MA (USA)

Pediatric renal tumor, Benign renal tumor, Trisomy 4



Ossifying renal tumor of infancy  (ORTI)  is an extremely rare benign pediatric renal tumor.

Clinics and Pathology


Less than 25 cases have been reported, mostly within the first year of life (age range 6d-30mths, mean 6.7m). There is a predilection for males (male to female ratio 6:1).

Clinical features

Presentation symptoms include painless gross hematuria and rarely with an abdominal mass. Unilateral mass located in the renal pelvis and calyces with occasional extension into the collecting ducts, leading to hydronephrosis or pelvicalyceal dilatation 1.  Rarely coexistence with other malignant tumors has been reported.

Macroscopic apperances

Nodular, often calcified mass with firm, grey-white, cut surface.


The tumor consists of core surrounded by osteoblasts blends at the periphery with a blastemal-like spindle cell component with infiltrative growth.  The osteoid matures with the age of the patient.


EMA, Vimentin and STAB2 were positive in osteoblasts and WT-1 in spindle cells; CK, PAX8 and PAX2 negative.


Prognosis and treatment

The tumor is benign, and so far, reported patients remain well without recurrence or metastasis after operation.2



Trisomy 4 has been reported in a small group of tumors.2-4


Reference NumberPubmed IDLast YearTitleAuthors
1246339112014The impact of race, age, and sex in follicular lymphoma: A comprehensive SEER analysis across consecutive treatment eras.Nabhan C et al
2276339112016Ossifying renal tumor of infancy (ORIT): The clinicopathological and cytogenetic feature of two cases and literature review.Guan W et al
3229762872013Clonal trisomy 4 cells detected in the ossifying renal tumor of infancy: study of 3 cases.Liu J et al
4291870242017Ossifying Renal Tumor of Infancy: Report of a Case With Positive WT1 Immunohistochemistry and High Mitotic Index and Review of the Literature.Vaillancourt B et al


Rita Alaggio ; Paola Dal Cin

Ossifying renal tumor of infancy

Atlas Genet Cytogenet Oncol Haematol. 2021-07-07

Online version: http://atlasgeneticsoncology.org/solid-tumor/208918/ossifying-renal-tumor-of-infancy