Cellularity: what is normal?

[J.claire]

I have been able to understand most of my bone marrow biopsy results, but I don’t understand cellularity 20%. Is this within the normal range. I was going to wait for my next visit, but if anyone here understands cellularity, I would be grateful if you could share your knowledge. Thank you.

[uno grasshopper]

Hi J. Claire:

Normal marrow cellularity ranges are gauged according to your age, and is a ball park figure depending upon which lab interprets your marrow sample. Basically, we have red marrow, which is the blood forming part of our marrow, and then we have yellow marrow, which consists of fat. The cellularity ratio refers to the ratio of red marrow to yellow marrow.

According to Textbook Hematology, normal adults have “about” a 1:1 ratio of fat to hematopoietic tissue (indicating 50% cellularity). A young child has the highest cellularity with about 65% hematopoietic tissue, whereas in the elderly, hematopoietic tissue decreases to about 30%.

William’s Hematology states the the normal cellularity is about 80% in early childhood to 50% by age 30, with further decreases after age 70.

My father’s latest BMB cellularity showed 20%. He is 75 years old, and currently has a normal CBC(reds, whites, and plts). His peripheral blood count is able to maintain at normal levels with 20% marrow cellularity.

Hope this helps!

Marla

[J.claire]

Your explanation really helps a lot. I had looked at several online sources and couldn’t find anything that made sense to me. Thank you so much. I am glad to hear that your father is doing well. Are you and MD? You certainly do understand biology, or whatever this is!

[uno grasshopper]

Hi J. Claire:

Glad to be of any help. No, I’m not an M.D., just a fellow “patient” traveler.

Take care,

Marla
aplastic anemia, diagnosed Oct 1999
last blood transfusion on July 6, 2001
reds and whites in normal ranges, plts around 118K

[Jack_dup1]

My BMB shows Hypercellular Bone Marrow 98%, looking at Marla’s explanation I should be back in the womb.
Jack

[Jim]

My celularity is similar to Jack’s. I’d like to know what it means in us older folks.

JW

[uno grasshopper]

Hi Jim:

I’ll share what I understand of it from my layperson’s perspective. As we all know, not only is having too little active marrow problematic, but having “too much” is also problematic. Too much active marrow (as with too many red cells, too many platelets, or too many whites) causes overcrowding and thus “clogging.” As an example, too many platelets can cause excessive clotting, which in turn can cause strokes. Too many whites can infiltrate organs causing pain, inflamation, and conditions similar to Sweet’s Syndrome. Too many reds can also cause too much pressure in the vessels and organs. Likewise, too much marrow can cause bones to weaken as it can place extra pressure on the interior of the bones. As an example, patients suffering from Thalassemia are anemic, not because they don’t have enough marrow to produce blood, but because their red cells are destroyed prematurely (and commonly doesn’t even mature at all). Therefore, their marrow ramps up production to try to make up for the anemia, and result is “hypercellular marrow.” This hypercellular marrow crowds the inside space of their bones, causing their bones to weaken, and that is one reason why Thalassemia patients have bone deformities and easy fractures. Now, I have not heard that explanation for MDSers or PCVers likely because this condition develops “after” the bones are fully grown, unlike in Thalassemia patients who are young and their bones haven’t fully developed yet. However, in PVCers since they tend to overproduce blood, the common treatment is phlebotomy to reduce their hct. But the problem that has been observed with “excessive” phlebotomies with PCVers is that it seems to speed up their disease condition to the point that their marrow becomes “scarred,” which I believe is also called the “spent stage.” When that happens then their condition switches from too many cells, to too little, and they become anemic. My “guess” is that over crowding in the marrow may cause fibrosis in the marrow (scarring), thus leaving less room or healthy tissue for growth of healthy cells. I don’t think all MDSers progress to that point, however, you can read up more on it if you look up “myelofibrosis.” As with these conditions, the “cause” is commonly stated as “idiopathic.” I’m sure there’s a lot more to it than what I have just written, but that’s the jist of it from what I understand.

Hope this helps,

Marla

[Jimbob]

I am not sure but I remember something about hypercellular is the volume and then, depending upon what is in that volume and how it is formed, it will show if one has CML or CMML or on the way to another form of leukemia. I was hypercellular in the marrow to the max with it pushing out blasts into the blood stream at 95% when I had my extreme leukemic event.
Jim

[Jack_dup1]

I’m 98% Hypercellular with 2% blasts in the marrow, 1% in the blood.
Jack

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