Isolated myelosarcoma development in an adolescent chronic myeloid leukemia patient with t(9;22)(q34;q11.2), +8, +14, +21, and der(1)(p36)

Additional chromosomal abnormalities are found in 5–20% of patients during chronic phase of chronic myeloid leukemia and in 60–80% preceding or accompanying blast crisis. These abnormalities are important in disease progression and, because they may occur before hematological and clinical symptoms, can be taken as a prognostic indicator. An adolescent with chronic myeloid leukemia initially presented with extreme thrombocytosis, increased megakaryopoiesis with dysmorphic features, and focal myelofibrosis in bone marrow examinations and then developed isolated myelosarcoma 1 year after onset, with t(9;22)(q34;q11.2), +8, +14, +21, and der(1)(p36).