Anaplastic sarcoma of the kidney with chromosomal abnormality: first report on cytogenetic findings.

We report a case of anaplastic sarcoma of the kidney (ASK) with cytogenetic findings. A 12-year-old Japanese girl presented with buttock pain and urinary incontinence. Radiological investigations revealed a right renal tumor with multiple distant metastases and multicystic thyroid tumor. She underwent radical right nephrectomy and subsequently received chemotherapy and radiation therapy. Histologically, the renal tumor demonstrated admixture of various types of mesenchymal elements: cellular spindle cells with anaplastic features, cartilage, and rhabdomyoblastic cells consistent with ASK. Chromosomal analysis revealed the karyotype of the tumor cells to be 46, XX, +8, -10, der (18) t (10; 18) (q21; p11.2). The thyroid tumor was removed later and diagnosed as adenomatous goiter. To our knowledge, this is the first case of ASK with chromosomal abnormality and may provide new insight into the molecular biologic basis of this rare renal tumor.