Cytology of well-differentiated and poorly differentiated hemangiosarcoma in fine needle aspirates.

The cytologic descriptions of fine needle aspirates from one well-differentiated and one poorly differentiated hemangiosarcoma are reported and correlated with the histologic findings. Aggregates of two to ten cells predominated in the aspirate from the well-differentiated tumor. In Papanicolaou-stained smears and filter preparations, single nuclei, resembling intravascular nuclear protrusions in a punch biopsy specimen, projected from some of these cell groups. Shallow longitudinal invaginations characterized the hyperchromatic nuclei. Erythrophagocytosis and cytoplasmic vacuoles were evident in Wright's-stained smears. Individual binucleate cells predominated in aspirates from the poorly differentiated tumor. Their nuclei exhibited thicker membranes, more prominent nucleoli and clearer parachromatin than did those of cells from the well-differentiated tumor. Cytoplasmic projections were common and sometimes quite complex. While these cytologic features are not pathognomonic, they are indicative of a malignant neoplasm and can be combined with clinical and other histopathologic data to provide a complete diagnosis.