What are Smudge Cells?
As cells have cytoplasmic membranes or nuclear structures that can be identified, with Smudge Cells, they have otherwise. These cells are mere remains of dead lymphocytes, of which make them clump up together, hence their other term “Basket Cells“.
In most cases, Smudge Cells are also classified as Lymphocytes, therefore including them in the absolute and relative differential counts. However, Smudge cells are not only found on those abnormal lymphocytes that are fragile but also on some lymphocytes that are deteriorating. (1,2)
In order for us to clearly identify the said cells, it would be best to view an image of it.
The image above presents the clear appearance of Smudge Cells on the left side, which are the clumped up cells that are Violet in color. (3)
Image Source: www.webpathology.com
Don’t get mistaken by the three dark violet colored cells that are in the middle because they are small mature-looking lymphocytes, and on the center is a condensed nuclear chromatin. If you are wondering as to what the appearance of Lymphoid cells in CLL is, then you are looking at it.
What Causes Smudge Cells?
Before we talk about the causes of Smudge Cell formation, we have to discuss Chronic Lymphocytic Leukemia (CLL) first. This type of cancer occurs when too many lymphocytes are produced by the bone marrow.
It is known to be the most common type of Leukemia that is diagnosed on adults, and this disease gets worse over time. So how is this related? Well, smudge cells are formed through a complex process.
The normal formation of CLL is when the nucleus occupies the entire cell thus leaving a thin cytoplasmic rim behind. However, Lymphocytes of CLL are exposed to external pressure, which then takes time to flatten out, crushing them during the film preparation.
This is when Smudge Cells are formed. With that, the preparation of the blood films contribute the most in formation of such. Expertise is this preparation is crucial as it is said to be the most common cause.
There has to be a certain manner of handling the slide spreader because if it is tilted a few degrees higher, it makes the spreading of the blood faster, thus forming a thick film having an uneven cell distribution. A negative effect will still happen if the procedure is done slowly because the opposite will occur. (4,5)
The Differential Diagnosis of Smudge Cells
Upon counting Lymphocytes, the relative differential is 0.24, which is basically rounded off as 24% of the white blood cells.
With regards to the absolute lymphocyte count, it is simply white blood cells multiplied by the relative lymphocyte count. Now as we move to the white blood cell differential, the numbers are not matching as the equivalent of all of the relative counts should be equivalent to 1.0 and the equivalent of all of the absolute counts has to be equal with the white blood cells.
There are certain innovative instruments that recognize WBC counts of which Smudge Cells are indeed Lymphocytes, therefore, including them into the count of relative and absolute matters.
If the Smudge Cells along with the absolute lymphocytes continue to rise, then the odds of a lymphoproliferative disorder such as CCL would be present. (6)
- Dr. Susan J. Leclair, PhD, CLS (NCA) – Boston, Massachusetts; Explaination of Lymphocytes; Retrieved from: firstname.lastname@example.org
- Smudge Cells; The medical definition of Smudge Cells; Retrieved from: https://www.labce.com/spg48905_smudge_cells.aspx
- Image of Smudge Cells; Retrieved from: http://www.webpathology.com/slides-13/slides/HemePath_Blood1.jpg
- Smudge Cells: What Technologists Need To Know; Retrieved from: http://www.biomed-austria.at/fachartikel/0205_MTA_Heft_4.pdf
- Chronic Lymphocytic Leukemia; Retrieved from: http://www.cancer.gov/types/leukemia/patient/cll-treatment-pdq
- Smudge Cells: Clarifying The Diagnosis; Retrieved from: http://www.parkhurstexchange.com/hematology/2007-02-15?zid=