Abstract

BACKGROUND
The differential diagnosis of Kaposi sarcoma includes many disease that range from benign disease to malignant tumors. However, little information is available about the immunohistochemical characteristics of Kaposi sarcoma.
METHODS
The expressions of 13 various proteins (HHV-8 LNA-1, Ki-67, bcl-2, p53, CD31, CD34, factor VIII, D2-40, vimentin, SMA, S-100, EMA, and c-kit) were evaluated immunohistochemically in 49 vascular tumors including 16 Kaposi sarcomas, 8 angiosarcomas, 2 hemangioendotheliomas, and 23 benign vascular tumors with using the tissue array method.
RESULTS
All 16 cases of Kaposi sarcoma showed nuclear staining for HHV-8 LNA-1, whereas all the cases of angiosarcoma and benign vascular lesions were negative for HHV-8 LNA-1 (p<0.001). All Kaposi sarcoma were positive for D2-40, which is a marker of lymphatic differentiation, but 25% of the benign vascular lesions and 30.4% of the angiosarcoma were positive for D2-40 (p<0.001). The mean proliferation index as assessed by Ki-67 immunostaining revealed no difference between the benign and malignant vascular lesions (p>0.05). No Kaposi sarcoma showed a bcl-2 expression, but 62.5% of the angiosarcomas and 21.7% of the benign vascular tumors had bcl-2 expressions (p=0.005).
CONCLUSIONS
Immunohistochemical detection of HHV-8 LNA-1 and D2-40 are useful tools to differentiate Kaposi sarcoma from other vascular tumors.

• Keywords: Sarcoma, Kaposi;Herpesvirus 8, human;Latent nuclear antigen;Monoclonal antibody D2-40;Immunohistochemistry