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

Enlarged nuclei: equal to or >3 times the size of a similar type of 
  adjacent cell 

Nuclear hyperchromatism 

Focal anaplasia (<10% of microscopic fields) 

Diffuse anaplasia (>10% of microscopic fields) 

Prognosis and anaplasia (diffuse) 
    55% relapse rate 
    48% mortality rate

Tubular predominant better prognosis than blastemal predominant 

Teratoid Wilms (adipose tissue, cartilage, squamous cells, glands): Better Prognosis 

Adenofibroma appearance: Better prognosis

Anaplasia absent in tumor extension beyond tumor capsule 

No evidence of severe nuclear atypia elsewhere in yumor 

With more than 1 focus, anaplastic area surrounded by non-anaplastic tumor 

Treated patients undergoing nephrectomy: 
    Discrete anaplastic foci with original primary tumor 
    Surrounded by non-anaplastic or necrotic tumor

Anaplasia with marked nuclear atypia elsewhere in tumor 

Anaplasia not demarcated from non-anaplastic tumor 

Anaplasia in intrarenal vascular extensions, extra-renal invasive sites or in metastases 

Anaplasia in random biopsy sample