A multinucleated cell is a cell with two or more nuclei. In hematologic disorders, if multinucleated cells are present, they are generally abnormal cells and are a pathologic condition. For example, in patients with acute leukemia, which is common in clinical practice, leukemia cells are easily found in the bone marrow, and during morphologic examination, multinucleated immature primitive cells, which generally contain two or more nuclei and have obvious nucleoli, are diagnosed as acute leukemia. Also, in patients with multiple myeloma, it is often easy to find multinucleated myeloma cells, which generally have a large cell morphology and also contain multiple nuclei. Therefore, multinucleated cells in hematologic disorders are generally referred to as hematologic malignancies. In normal individuals, human myeloid cells also contain multiple nuclei, which is a normal structure.