Diffuse bone marrow metastases of small cell carcinoma with associated erythrophagocytosis mimicking acute leukaemia

Unknown primary malignant small round cell tumor masquerading as acute leukemia

“…Unknown primary MSRCT masquerading as leukemia is rare; however, immunohistochemical staining should be performed to assist accurate diagnosis if the blasts exhibit abnormal expression of surface antigens. [3][4][5] CD45-negative leukemia-like findings of BM should be differentiated from all MRSCTs.…”