Conventional Angiosarcoma

Abstract: Eight cases of a previously uncharacterized vascular neoplasm, showing varying combinations of benign, low-grade malignant, and malignant vascular components are described. Seven tumors occurred in the dermis and/or subcutis and one occurred in the oral submucosa. The patients were all adults with a median age of 39.5 years (range, 21-71 years). Five patients were men. The tumors arose predominantly in the hands and feet, and the lesions were usually of several years duration. The tumors were composed of a complex admixture of histologic components that varied from tumor to tumor, such that no two tumors looked precisely the same. This was due to variation in the proportions of each component as well as the manner in which each component was distributed throughout each lesion. The predominant histologic components were epithelioid hemangioendothelioma (HE) and retiform HE, which were each present in seven of the tumors. Areas of spindle cell HE were identified in four lesions. Angiosarcoma-like elements were identified in seven tumors. One of the tumors was associated with an arteriovenous malformation and one was associated with an area of lymphangioma circumscriptum. Of six cases with follow up (median duration, 6.5 years), three have recurred locally and, to date, only one has metastasized. We think composite HE is best regarded as a low-grade malignant vascular neoplasm, and the available data suggest that it behaves more favorably than conventional angiosarcoma. The existence of these composite lesions has led to careful reexamination of the concept of HE. The term HE, in that it is currently synonymous with a low-grade malignant vascular tumor, should be reserved for lesions that have true metastatic potential, albeit with low frequency.

Abstract: Background We have encountered cases of post-radiation angiosarcoma (PRAS) histologically mimicking radiation dermatitis. Methods Cases of PRAS from institutional/consultation archives from 2006 to 2016 were reviewed. For inclusion, tumors had to have inapparent/subtle tumor at low magnification and scattered individual tumor cells resembling radiation fibroblasts. Prior ancillary studies were reviewed, with additional immunostains performed as needed. Results 10 cases met criteria. All occurred in women treated for breast cancer (mean age 71 years). All had similar findings: in particular, scattered single atypical cells with pleomorphic nuclei associated with microscopic hemorrhage. They also had narrow, slightly wavy “worm-like” vascular channels lined by atypical endothelial cells that lacked architectural complexity. Four cases showed focal areas of more conventional angiosarcoma. One case was an excision of a large mass that showed the “radiation dermatitis-like” pattern radiating out from the central mass. All were positive for vascular markers (CD31, CD34, and/or ERG) and MYC. MYC amplification was demonstrated by FISH in both cases tested. In 3 of 3 cases with available re-excision specimens, more obvious angiosarcoma was seen. Conclusions PRAS can be very subtle and histologically mimic radiation dermatitis. Careful attention to histologic features and ancillary tests allow accurate diagnosis in subtle PRAS.