Our patient had missense mutations in the FLT3 and PTPRB genes, which are associated with myeloid sarcoma; missense mutations in LTK (associated with poorly differentiated cancer), NOTCH2 (associated with diffuse large B-cell tumor), and CNTN2 (associated with T-cell lymphoma); and a frameshift deletion mutation in the oncogene TP53. We also reviewed the relevant literature from 1990 to 2021, and identified 10 cases of myeloid sarcoma with monocytic differentiation. The gene discussed is CNTN2; the disease is myeloid sarcoma.