Cytologic features of angiosarcoma: A review of 26 cases diagnosed on FNA.

Background: This study describes the cytologic features of 26 angiosarcomas diagnosed on fine-needle aspiration.

Methods: Twenty-six angiosarcomas from 20 patients were confirmed by cytomorphology and immunocytochemical (immunohistochemistry) positivity for at least 2 of 3 vascular markers. Specimens were examined for spindled/epithelioid/plasmacytoid single cells, 3-dimensional clusters, multiple prominent/bar-shaped nucleoli (5 times longer than their width), chromatin strands, abnormal mitoses, necrosis, and vasoformative features.

Results: Eight males and 12 females with a mean age of 52 years (range, 2-94 years) underwent aspiration of tumors in the following: soft tissue or skin/subcutis (n = 10), bone (n = 4), nodes (n = 5), lung (n = 2), liver (n = 2), heart (n = 1), parotid gland (n = 1), and pleural fluid (n = 1). An angiosarcoma diagnosis was rendered for 24 of the 26 cases (92%); 1 was diagnosed as "atypical cells, cannot exclude angiosarcoma," and another was diagnosed as a malignant vascular neoplasm. Abnormal mitoses were most frequent (85%), and they were followed by single malignant cells (81%: epithelioid [69%], spindled [62%], and plasmacytoid [19%]), 3-dimensional clusters (54%), multiple prominent (62%) or bar-shaped nucleoli (54%), and chromatin strands (31%). Vasoformative features, including hemophagocytosis (54%), cytoplasmic lumina/vacuoles (69%) containing red blood cells (54%)/neutrophils (31%), and endothelial wrapping (69%), were seen in 88%; 23% had all vasoformative features, 88% had at least 1, and 12% had none.

Conclusions: Angiosarcomas show a range of cytomorphologic features that make them potentially recognizable on cytology. Although vasoformative features are highly suggestive, they are not specific for angiosarcoma and may be seen in some nonvascular neoplasms. Immunohistochemistry and a high index of suspicion are required for an accurate diagnosis. Cancer Cytopathol 2016;124:659-68. © 2016 American Cancer Society.