谢谢老师

 细胞学异型性显著，倾向恶性，本人有如下考虑：

1. Angiosarcoma of the scalp. CD31+, CD34+, Factor VIII+.  非常少见的肿瘤, 但常见于老年人头颈部. 该例形态学和年龄不典型.

2. Poorly differentiated squamous cell carcinoma. CK5/6+. Commonly seen in old patient.

3. Melanoma. Always need to rule out melanoma for every strange skin malignant tumor. Do S100 first, very sensitive, but not specific. If Positive, can do other melanocytic markers, HMB45, MART1 or MITF.

4. Atypical fibroxanthoma. When other malignant tumor is ruled out, this is the likely diagnosis.

5. Malignant tumors of smooth muscle (SMA+) or neurofiber (S100+)

6. More history of this patient to rule out some weird metastatic tumor.

7. More pictures, especially lower power to rule out a benign process.

 上皮样血管内皮瘤 。

上皮样血管内皮瘤

 符合上皮样血管内皮瘤。术后要随访。