This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'All of the following immunohistochemical markers are positive in the neoplastic cells of granulocytic sarcoma, except - \nSelect and explain. \nA. CD45RO, B. CD43, C. Myeloperoxidase, D. Lysozyme', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Granulocytic sarcoma\xa0(Chloroma or myeloblastoma)\n\nGranulocytic sarcoma\xa0or chloroma is a solid tumor composed of myeloblasts.\nA chloroma is an extramedullary manifestation of AML, i.e., it is a solid collection of leukemic cells occurring outside of the bone marrow.\nThese tumor often have a green tint due to the presence of myeloperoxidase.\nChloromas are more common in monocytic differentiation (M4 & M5 type) AML.\nThough chloromas occur most commonly in patients with AML, they may also occur in a patient with : -\n\n\nMyelodysplastic syndrome\nMyeloproliferative syndromes → Myelofibrosis, CML, Polycythemia Vera, Essential thrombocytosis\nWithout concomitant disease, i.e., Primary chloroma.\n\n\nChloromas are positive for : -\n\nCD 68\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 CD 20\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 CD 117\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Lysozyme\nCD 43\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 CD 34\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Myeloperoxidase', 'role': 'assistant'}]