Physical exam was unremarkable with no evidence of lymphadenopathy or splenomegaly. There are numerous small megakaryocytes with hypolobated nuclei. The findings of macrocytic anemia, thrombocytosis, numerous small hypolobated seen on bone marrow biopsy, and deletion of long arm of chromosome 5 are diagnostic of 5q- Syndrome. 5q- Syndrome is classified as a myelodysplastic syndrome, and is generally associated with a good prognosis. This hematologic disorder is characterized by refractory anemia with a chromosome 5q deletion as the sole karyotypic abnormality of the bone marrow.
Most patients have a stable clinical course but are often transfusion dependent.
Very few of these patients transform to an acute leukemia. Although the specific molecular abnormalities in 5q- myeloid disorders are unknown, inactivation of one or more genes in the 5q31q33 segment is critical. This region, critical to the 5q- syndrome, appears to be distinct from the other 5q regions associated with MDS and myeloid leukemia. Practical Diagnosis of Hematologic Disorders, 3rd ed. Kjeldsberg, Carl, et al. 2000.