ASPIRATION BIOPSY CYTOLOGY OF MALIGNANT HEMANGIOPERICYTOMA METASTATICTO THE LUNGS - CYTOMORPHOLOGIC AND IMMUNOCYTOCHEMICAL STUDY OF A CASE

BACKGROUND: Hemangiopericytoma (HP) is an uncommon, slowly growing tum or that originates in ''pericyte'' cells. Biologically it can be benig n or malignant; however, it is difficult to predict tumor behavior bas ed on histomorphology alone. The cytomorphology of this tumor has been described only rarely. Other spindle cell mesenchymal tumors cart mim ic HP on fine needle aspiration biopsy (FNAB). CASE: A 60-year-old man presented with cough and a left lung mass on chest roentgenography an d multiple smaller bilateral lung Modules on computed tomographic scan . FNAB of the dominant left lung mass showed a moderately cellular asp irate with clusters and single spindle-shaped cells morphologically si milar to those of hemangiopericytoma excised from the posterior part o f the neck II years previously. With immunocytochemical studies, the t umor cells were negative for cytokeratin, factor VIII-related antigen, S-100 protein and HHF35 but positive for vimentin and CD34. CONCLUSIO N: FNAB is a valuable tool in evaluating nonepithelial metastatic lung tumors. In the appropriate clinical setting, it is possible to render a diagnosis of HP on FNAB in patients with previously documented HP b ased on morphologic comparison and ancillary studies, especially immun ocytochemical stains.