Chemotherapy-induced histologic changes in Wilms' tumors

Area of Science:

• Pediatric Oncology
• Nephrology
• Pathology

Background:

• Wilms tumor is a common pediatric kidney cancer.
• Preoperative chemotherapy is a standard treatment modality for Wilms tumor.
• Understanding chemotherapy's pathological effects is crucial for treatment optimization.

Purpose of the Study:

• To pathologically evaluate the effects of preoperative chemotherapy on Wilms tumor histology.
• To compare chemotherapy-treated tumors with a control group of untreated Wilms tumors.
• To determine the susceptibility of different Wilms tumor elements to chemotherapy.

Main Methods:

• Pathological examination of 21 nephrectomy specimens from patients treated with vincristine and actinomycin D chemotherapy.
• Review of 20 control specimens from untreated Wilms tumor patients.
• Histological analysis focusing on stromal, blastematous, differentiated, and vascular components.

Main Results:

• Diffuse histological changes observed in chemotherapy-treated tumors, primarily affecting the undifferentiated stroma (edema, fibrovascular background, histiocytes).
• Blastematous nodules showed reduction in size and necrosis in 5 cases.
• Vascular changes (fibrinoid necrosis, thrombosis, inflammation) were prominent in 15 treated tumors.
• Differentiated elements (glomeruloid, tubular, rhabdomyoblastic) were largely unaffected.
• Minimal and focal histological changes noted in the control group.

Conclusions:

• Preoperative chemotherapy significantly alters Wilms tumor histology, particularly in stromal and vascular tissues.
• The study defines the differential susceptibility of Wilms tumor components to chemotherapy.
• Chemotherapy-induced changes are more pronounced and diffuse compared to minimal changes in untreated tumors.