Megakaryocyte nucleus hyperlobulation

What it means

The presence of megakaryocytes in the bone marrow whose nuclei are more lobulated than expected for the size of the nucleus.

A large megakaryocyte with a hyperlobulated nucleus is a cell that is larger than average size and has more nuclear lobulation than average. Some such megakaryocytes are seen in normal bone marrows but when they are present as an increased proportion they should be commented on. Increased numbers are seen sometimes in myelodysplastic syndrome but they are more frequent in myelodysplastic/myeloproliferative neoplasms (MDS/MPN) and in MPN, particularly essential thrombocythemia.

Rare diseases that can present with this1

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