Aspiration biopsy cytology of malignant hemangiopericytoma metastatic to the lungs. Cytomorphologic and immunocytochemical study of a case

Hemangiopericytoma (HP) is an uncommon, slowly growing tumor that originates in "pericyte" cells. Biologically it can be benign or malignant; however, it is difficult to predict tumor behavior based on histomorphology alone. The cytomorphology of this tumor has been described only rarely. Other spindle cell mesenchymal tumors can mimic HP on fine needle aspiration biopsy (FNAB).A 60-year-old man presented with cough and a left lung mass on chest roentgenography and multiple smaller bilateral lung nodules on computed tomographic scan. FNAB of the dominant left lung mass showed a moderately cellular aspirate with clusters and single spindle-shaped cells morphologically similar to those of hemangiopericytoma excised from the posterior part of the neck 11 years previously. With immunocytochemical studies, the tumor cells were negative for cytokeratin, factor VIII-related antigen, S-100 protein and HHF35 but positive for vimentin and CD34.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 based on morphologic comparison and ancillary studies, especially immunocytochemical stains.