FINE-NEEDLE ASPIRATION CYTODIAGNOSIS OF LEIOMYOSARCOMA OF THE RENAL PELVIS - A CASE-REPORT WITH IMMUNOHISTOCHEMICAL STUDY

Leiomyosarcoma of the renal pelvis is extremely rare. We report one su ch case correctly diagnosed by ultrasound-guided fine needle aspiratio n cytology (FNAC), The FNAC smears showed a monotonous population of c losely packed, spindled tumor cells arranged in interlacing bundles. T hose cells possessed markedly pleomorphic, hyperchromatic, elongated n uclei and a moderate amount of eosinophilic, fibrillary cytoplasm. Fas cicles of similar spindle tumor cells arranged in a whorled pattern we re seen in the section of the cell block. Immunohistochemistry was per formed on the sections of the cell block preparation, showing intensel y positive cytoplasmic staining of the tumor cells for muscle-specific actin but negative staining for CAM 5.2, AE1/AE3, S-100 protein and H MB-45. This staining pattern of the tumor allows its differentiation f rom other primary sarcomas of the kidney, sarcomatoid renal cell carci noma, peripheral nerve sheath tumor and renal angiomyolipoma. The extr eme degree of nuclear pleomorphism and hyperchromatism is not to be ex pected in renal leiomyoma or the usual cases of mesoblastic nephroma. Besides delineating the FNAC features of leiomyosarcoma of the renal p elvis, the present case illustrates the value of using the cell block preparation in FNAC.