Megaloblastic bone marrow

What it means

Abnormal increased number of megaloblasts in the bone marrow.

A megaloblast is an abnormally large nucleated red blood cell found especially in people with pernicious anemia. Megaloblasts, like their normal counterparts, normoblasts, are immature red cell precursors in the bone marrow. Megaloblasts display both a larger size than normoblasts as well as a fine reticular nuclear structure.

Rare diseases that can present with this4

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category