HISTOLOGY Bone marrow aspiration and biospy required for diagnosis and staging 1. Lymphoma2. Ewings Small round cell tumor 1. Lymphoma2. Leukemia3. Ewing's sarcoma4. Metastatic carcinoma (small cell lung) 5. Rhabdomyosarcoma6. Neuroblastoma Epithelial Glands seen on histology 1. Synovial sarcoma (biphasic)2. Metastatic carcinoma3. Glomus tumor Bimorphic histology 1. Dedifferentiated chondrosarcoma2. Synovial sarcoma3. Osteosarcoma with chondroblastic features Multi-nucleated Giant cells present 1. Giant cell tumor2. Chondroblastoma3. Aneurysmal bone cyst Hemosiderin pigmentation 1. NOF2. PVNS3. UBC IMMUNOSTAINS Leukocyte common antigen 1. Lymphoma CD138 1. Myeloma CD99 1. Ewing's CD1A 1. EG CD34 1. DFSP2. Angiosarcoma CD20 (B cell) 1. Lymphoma S100 1. EG2. Chordoma3. Melanoma 4. Clear cell sarcoma5. Nerve sheath tumors (Schwanoma) Elastin 1. Elastofibroma Keratin 1. Metastatic bone disease2. Synovial sarcoma3. Chordoma4. Epitheloid sarcoma5. Adamantinoma Factor VIII 1. Angiosarcoma Smooth muscle actin 1. Leiomyosarcoma Desmin 1. Rhabdomyosarcoma Myoglobin 1. Rhabdomyosarcoma CK7 1. Breast CA2. Lung CA CK125 1. Ovarian CA CK20 1. Colon CA TTF1 1. Lung CA EMA 1. Synovial sarcoma