Deceptively bland cutaneous angiosarcoma on the nose mimicking hemangioma-A clinicopathologic and immunohistochemical analysis.

BACKGROUND: We investigated 2 cases of deceptively bland cutaneous angiosarcoma (AS), which showed a uniform clinical presentation with a rapidly growing tumor on the nose. It remains unclear whether this was a primary cutaneous manifestation or a metastasis. Both tumors initially presented a high histologic overlap with a benign vascular tumor. The diagnosis was primarily based on the rapidly progressing clinical course and on the results of the staging procedures.

METHODS: Immunohistochemical stains were performed for cytokeratin (AE1/AE3 and MNF116), CD31, ERG, CD34 (HPCA1/my10), D2-40/podoplanin, LYVE-1, Ki67, PHH3, αSMA (1A4), MYC, FOS-B, CAMTA-1, TFE-3, WT1, nestin, VEGFR-2(KDR), VEGFR-3(FLT4), HHV8. MYC amplification was also investigated by fluorescence in situ hybridization.

RESULTS: The tumor cells were negative for MYC and revealed no D2-40/podoplanin expression. SMA-positive pericytes formed rims around the vessel. The proliferative activity (Ki-67) was elevated, in one case only in a later stage.

DISCUSSION: Cutaneous ASs can be rather bland and may easily be mistaken for benign vascular tumors. Both cases presented a uniform clinical picture, which implied a malignant vascular tumor. In contrast, the cytomorphology of the endothelial cells and the immunohistochemical profile were not suspicious. We worked out subtle histological criteria, which should allow an early detection of such tumors.