Hypocellular is a term pathologists use to describe a decreased number of cells compared to normal in that area of the body. It is a descriptive term and not a diagnosis. Hypocellular can be used to describe both benign (non-cancerous) groups of cells and malignant (cancerous) tumours. Pathologists commonly use the term hypocellular when describing the changes seen in a bone marrow biopsy where there is a decreased number of cells compared to what is normally present in the bone marrow. The opposite of hypocellular is hypercellular.