Atypical myeloproliferative disorder associated with a 21 trisomic clone.

The hematological and cytogenetical studies of a case of atypical myeloproliferative disorder are reported. The patient displayed moderate leukocytosis, anemia and thrombocytopenia. Reduced or absent growth of CFU-C was observed in the bone marrow and peripheral blood. The cytogenetical analysis revealed a trisomy 21 limited to the neoplastic clone. The overall results are discussed and compared with the rare cases of acquired trisomy 21 reported in the literature.