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Rhabdoid TumorALL Non-CNS rhabdoid tumors treated on the High Risk Renal Tumor Protocol

Genetic Evaluation for INI-1 deletions and BAF47 expression performed on all patients

Treatment: New regimen

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Diagnostic Difficulties

Pseudo-Rhabdoid Phenotype in Primary Renal Tumors and Metastatic Tumors– INI-1 Positive in Pseudo-Rhabdoid Tumors

Biopsy of Extra-Renal Mass

Mistaken for Rhabdomyosarcoma (RT negative for myogenic markers)

Sclerosing Pattern Resembles DSRCT

Congenital Mesoblastic Nephroma

Median Age at Diagnosis 2 Months90% in 1st Year of Life (not reported >2yr of age)Most Common Congenital Tumor of the KidneyDetection In Utero: Abdominal Mass, Polyhydramnios, Hydrops & Premature DeliverySize 0.8 to 14 cm (median 6.2cm)Solitary, Unilateral Soft to Firm Masses with Bulging Cut SurfaceCysts, Hemorrhage & Necrosis CommonNot Associated with WT or NR (rarely in BWS)

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Congenital Mesoblastic Nephroma

Classic 22% Infantile fibromatosis

Cellular 58% Infantile

fibrosarcoma

Mixed 20%

Mean age all 4.4 moMean age classic 3.2 moMean age cellular 4.9 mo

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CMN: Classic vs Cellular

Classic– Interface with Kidney:

Irregular, Interdigitating

– Elongated Spindled Cells

– Infantile Fibromatosis Appearance

– Cytogenetics: ?– Mean Age: 3.2 Months

Cellular– Interface with Kidney:

Circumscribed, Not Encapsulated

– Plump, Slightly Spindled Cells

– Infantile Fibrosarcoma Appearance

– t(12;15) – ETV6/NTRK3– Mean Age: – 4.9 Months

Hypercalcemia: Prostaglandin E Produced by TumorHyperreninism: Entrapped Normal Renal Elements

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t(12;15) ETV6/NTRK3

Cellular Mesoblastic Nephroma

– (Congenital Infantile Renal Fibrosarcoma)

Congenital Infantile Fibrosarcoma

Secretory Breast Carcinoma

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CMN: Outcome29/415 (7%) patients recurred– 91 classic, 235 cellular, 80 mixed

All recurrences were cellular

All recurrences with cellular or mixed CMN– Local recurrence: 20 cases (88%

stage 3 at dx)

– Distant metastasis: 9 cases (lung)

Time elapsed from diagnosis to recurrence: 2-11.5 months (mean 5.5)

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CMN: ConclusionsMost Important Determinant of Recurrence is Histologic Subtype

Stage 3 disease in Cellular CMN Correlates with Local Recurrence

Cellular CMN Treated With Infantile Fibrosarcoma Therapy– No adjuvant therapy if no gross residual

tumor– Adjuvant chemotherapy if residual tumor

Cellular CMNs with Microscopic Residual Disease Monthly Abdominal US for 1 Year

Diagnostic Difficulties in CMN

Cellular CMN – Mistaken for Clear Cell Sarcoma of Kidney, Rhabdoid Tumor or Primitive Sarcoma

Stromal WT – Indistinct Border & SMA in CMN; Blastema & WT1 in WT

Metastatic CMN – Confused with Other Spindle Cell Malignancies

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Ossifying Renal Tumor of Infancy

Rare Tumor 1st Described in 1980Hematuria Presenting SymptomMost in Boys <1 Yr OldSmall Calcified Mass in Renal Pelvis Attached to Renal Parenchyma at or near the Papilla – Mass Lies “Free” in Renal PelvisMimic Renal Calculus Clinically and RadiologicallyExcellent Prognosis With No Recurrences or Metastases

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Gene Expression

Patterns (CMN=Black;

CCSK =Green; RT=Red; WT=Blue)

Gene Expression

Patterns (CMN=Black;

CCSK =Green; RT=Red; WT=Blue)