The co-expression of cytokeratin and p63 in epithelioid angiosarcoma of the parotid gland: a diagnostic pitfall

Abstract

Epithelioid angiosarcoma of the parotid gland is rare, and may pose a great diagnostic challenge. We report a case of primary epithelioid angiosarcoma in a 64-year-old male without history of radiation. The histopathological findings demonstrated a high grade epithelioid neoplasm. Immunostaining showed that the tumor was positive for the pan-cytokeratin, p63, cytokeratin18, Vimentin and vascular markers CD31, and was negative for CD34, cytokeratin5/6, cytokeratin7, cytokeratin20, CD68, CD30, S-100, HMB45, desmin, α-SMA and CD45. The tumor was diagnosed as an epithelioid angiosarcoma. To our knowledge, this is the first reported case of angiosarcoma which showed common positivity for cytokeratin and p63. In addition to cytokeratin, p63 is considered a useful marker for carcinoma. The co-expression of cytokeratin and p63 in epithelioid angiosarcoma represents a diagnostic pitfall. Thus, using a panel of antibodies is essential for distinguishing this tumor from poorly differentiated carcinoma. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6548916707504750.

Figure 1

A, The tumor cells were arranged in nests on the right area (green arrow); while the normal parotid gland tissue was on the left area (red arrow). B, The area of necrosis and hemorrhage could also be seen easily (black arrow). C, The large vascular spaces could be seen on peripheral area of the whole section. D, Solid areas showed anaplastic cells with prominent nucleoli and no clear-cut vasoformation.

Figure 2

A, Diffuse pankeratin staining highlighted the tumor cells. B, The majority of the tumor cells was positive for p63. C, Diffuse and strong expression of CD31could be seen in the tumor cells. D, Almost 50% of tumor cells were positive for Ki67.