Ossifying Renal Tumor of Infancy: A Clinicopathologic Study of Nine Cases

Abstract

We studied nine ossifying renal tumors of infancy (ORTI), including all five previously reported cases. There were eight boys and one girl ranging in age from 6 days to 14 months. Gross hematuria was the presenting sign in all nine patients. Eight tumors arose in the left kidney and six in the upper pole. All seven patients with follow-up information were free of recurrence. All lesions were attached to a renal papilla and presented mainly within the calyceal lumen. Two resembled staghorn calculi clinically. All tumors contained varying proportions of osteoid, osteoblastic cells, and spindle cells. The spindle cell component had features strongly suggesting that they represented hyperplastic intralobar nephrogenic rests (ILNR). The proportion of osteoid and degree of osseous maturation increased with increasing age of the patient. ORTI is a distinctive clinicopathologic entity, possibly representing a distinctive interaction between ILNR in the renal papilla with distal collecting duct or urothelial cells in the developing kidney.

An Approach to Renal Masses in Pediatrics

“…This may be useful in characterizing nonneoplastic renal pseudotumors, which are masslike imaging findings that mimic neoplasms. 6 The presence of flank pain, fever, or pyuria, for example, is suggestive of an infective process, such as pyelonephritis, instead of a tumor. However, the absence of symptoms neither suggests nor refutes a diagnosis of malignancy.…”

Clonal trisomy 4 cells detected in the ossifying renal tumor of infancy: study of 3 cases

“…Those archival cases had been the object of the original description of the tumor, 1 and had been also included in a later review article analyzing nine cases. 2 …”

“…3 The tumor has not been shown to be related to any of the well-established syndromes or infantile renal tumors such as the Wilms tumor or the Mesoblastic Nephroma, albeit the kidney of one case was reported as also harboring intralobar nephroblastomatosis. 2 The karyotypic makeup of the process has not been described, which is prompting this communication of our finding of clonal trisomy 4 in cultured tumor cells. This aneuploidy was also detected and confirmed by the fluorescent in-situ hybridization (FISH) probing of the tumor as well as two additional archival formalin-fixed, paraffinimbedded (FFPE) ossifying renal tumors of infancy.…”

“…The neoplasm is primarily characterized by the presence of a large ossifying component. 2 Its most common mode of presentation is hematuria, as it usually mushrooms and bulges into the pelvi-caliceal system. This neoplasm has a uniformly benign behavior.…”

Case report and literature review of a rare diagnosis of ossifying renal tumor of infancy

“…1 To date, there are 16 reported cases. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] We describe a 4-month old boy with ORTI who was treated with a radical nephrectomy. At his 2-month follow-up, he was without recurrence.…”