SPINDLE-CELL SARCOMA OF THE KIDNEY WITH GANGLIONIC ELEMENTS (MALIGNANT ECTOMESENCHYMOMA) ASSOCIATED WITH CHROMOSOMAL-ABNORMALITIES AND A REVIEW OF THE LITERATURE

Purpose: Malignant ectomesenchymomas are tumors that exhibit both mese nchymal and neuroectodermal elements (1). We report a case thought to represent a malignant ectomesenchymoma arising in the kidney with cyto genetic abnormalities that may provide insight into the biologic basis for this unusual tumor. Methods: We discuss the clinical features, hi stopathologic findings, cytogenetics, treatment, and outcome of a chil d with a malignant ectomesenchymoma arising in the kidney. Results: An asymptomatic 16-month-old boy had a large abdominal mass. The resecte d tumor contained sheets of spindled cells that expressed mesenchymal markers and cartilaginous differentiation, interspersed with clusters of ganglion cells that expressed neural markers. No blastemal or epith elial elements were demonstrated. Cytogenetic analysis of the tumor re vealed a hyperdiploid count with multiple numerical and structural abn ormalities. including a translocation between chromosomes 12 and 15. i n addition to the surgical resection, the patient was successfully tre ated with adjuvant chemotherapy and local radiation therapy. Conclusio n: This is the first report of which we are aware of an ectomesenchymo ma arising within the kidney. A subset of malignant ectomesenchymomas may be related to the Ewing's family of tumors (EFTs) (2), but this ca se did not exhibit cytogenetic features consistent with EFT. Thus, the malignant ectomesenchymoma phenotype probably represents a heterogene ous group of tumors with different genotypes and origins. Cytogenetic analysis may be instrumental in determining the appropriate therapeuti c approach when faced with such a neoplasm. The outcomes of 12 other c hildren with ectomesenchymoma are reviewed.