From Libre Pathology
CD99 is a commonly available immunostain with various uses. It stains a lot of different tumour and has been described by one soft tissue pathologist as slutty.
- Ewing sarcoma - diffuse (plasma membrane) staining.
- Lymphoblastic lymphoma/leukemia.
- Angiomatoid fibrous histiocytoma.
- Desmoplastic small round cell tumour.
- Squamous cell carcinoma.
- Undifferentiated small round cell sarcoma with t(4;19) (CIC-DUX sarcoma) - negative or weak positive.