Acta cytologica

0001-5547 51 4 2007 Jul-Aug Acta cytologica Acta Cytol. Primary intramuscular infestation of Echinococcus granulosus misdiagnosed as a soft tissue tumor: a case report. 631-3 The occurrence of a primary intramuscular infestation of Echinococcus granulosus is extremely rare. A 70-year-old woman with primary skeletal muscle hydatidosis initially presented with a soft tissue mass. Clinical and radiologic examination revealed a huge cystic mass in the right quadriceps muscle without any visceral organ involvement. Since the differential diagnosis included a soft tissue tumor, fine needle aspiration cytology was performed, and a diagnosis of hydatid disease was made. This very rare case of primary intramuscular infestation of E granulosus was clinically misdiagnosed as a soft tissue tumor. Hydatid disease, albeit rare, should be considered in the differential diagnosis of a soft tissue mass. Insabato Luigi L Section of Pathology, Department of Biomorphological and Functional Sciences, University of Naples "Federico II", Naples, Italy. insabato@unina.it Marino Gilda G Fazioli Flavio F Iacono Venanzio V Mascolo Massimo M Palombini Lucio L eng Case Reports Journal Article