Bone Metastasizing Renal Tumor of Childhood: A Clinicopathological Study of Eleven Cases from the Praguepediatric Tumor Registry
Abstract
Eleven patients with bone metastasizing renal tumor of childhood (BMRTCh) whowere diagnosed and treated in our departments over a 20-year period were reviewed. The incidence among all malignant renal tumors in children up to 15 years of age in our files was 3.7%.
The male to female ratio was 10:1. The morphology had a uniform, predominantly clear cell finely vascularized pattern in all of them.
Various previously recognized variations of the classic pattern such as hyalinization, nuclear palisading and cyst formation were observed in some patients. Electron microscopy showed that coarse vacuolization of the tumor seen at the light microscopic level was due to distended extracellular spaces surrounded by tumor cells and their cytoplasmic processes.
Immunohistochemistry of the tumor cells revealed positive vimentin in all cases, and focally positive muscle specific actin in one. A prominent feature was fascicles of perivascular spindle cells.
They were considered to be tumor cells rather than stromal elements since their morphology was close to the appearance of the polygonal tumor cells. The follow up data were available for ten patients.
Four developed bone metastases, three of them died of the disease progression. Another patient died of lymph node dissemination and gastrointestinal bleeding.
Six patients survived for a period of 29 months to 14 years following the diagnosis.