Purpose: Malignant ectomesenchymomas are tumors that exhibit both mesenchymal and neurocctodermal elements (1 ). We report a case thought to represent a malignant ectomcsenchymoma arising in the kidney with cytogenelic abnormalities that may provide insight into the biologic basis tor this unusual tumor.
Methods: We discuss the clinical features, histopathologic findings, cytogenetics, treatment, and outcome of a child with a malignant ectomesenchymoma arising in the kidney.
Results: An asymptomatic 16-month-old boy had a large abdominal mass. The resected tumor contained sheets of spindled cells that expressed mesenchymal markers and eartilaginous differentiation, interspersed with clusters of ganglion cells that expressed neural markers. No blastemal or epithelial elements were demonstrated. Cytogenetic analysis of the tumor revealed a hyperdiploid count with multiple numerical and structural abnormalities, including a translocation between chromosomes 12 and 15. In addition to the surgical resection, the patient was successful) treated with adjuvant chemotherapy and local radiation therapy.
Conclusion: This is the tirst report of which we are aware of an ectomesenchymoma arising within the kidney. A subset of malignant ectomesenchymomas may be related to the Ewing's family of tumors (EHTs) (2). but this case did not exhibit cytogenctic features consistent with EFT. Thus, the malignant ectomcscnchymoma phenotype probably represents a heterogeneous group of tumors with different genotypes and origins, Cytogenctic analysis may be instrumental in determining the appropriate therapeutic approach when faced with such a neoplasm. The outcomes of 12 other children with ectomesenchymoma are reviewed.