A rare atypical myeloproliferative-disorder-like hemopathy with marked dysplasia, peripheral dominant myeloblast proliferation and extramedullary hematopoiesis was converted into typical acute myeloid leukemia with an interval of complete hematological remission.

We describe a patient with leukocytosis with all the stages of neutrophilic series, peripheral dominant myeloblast proliferation, marked dysplasia of myeloid and erythroid series, and extramedullary hematopoiesis of the lymph nodes. A cytogenetic study of the bone marrow cells showed normal karyotype, and molecular analysis of the leukemic cells showed negative for BCR-ABL by RT-PCR. After chemotherapy, the patient went into complete remission with a normal blood and bone marrow profile with no dysplasia. On relapse, the hematological findings showed a typical bone marrow dominant acute myeloid leukemia, with the leukemic cells having a chromosomal abnormality. The patient exhibited the combined features of myeloproliferative disorder, myelodysplastic syndrome, peripheral dominant myeloblast proliferation (so-called peripheral leukemia) and typical acute myeloid leukemia throughout the clinical course. This is thought to be a rare overlapping disease involving these distinct hematological conditions that do not usually occur in the same patient.