The relationship between the thyroid hormone (or its lack) and dysplastic hematopoiesis.

Anemia is common in hypothyroidism and is considered to be an adjustment to a decreased basal metabolism. It is characterized by reticulopenia, erythroid hypoplasia, and a decreased level of endogenous erythropoietin. It is possible that the thyroid insufficiency, and the consequent arrested hematopoiesis, hinder or prevent the fullblown bone marrow dysplastic features of MDS from manifesting. The replacement treatment, by correcting the hypoproliferative status, makes the dysplastic abnormalities more conspicuous and concomitant MDS more evident, the possible reason for partial or no hemoglobin response. Continued attention to thyroid function therefore seems essential in the diagnosis and management of MDS.