They are teardrop-shaped erythrocytes most commonly seen in peripheral blood smears from patients with primary or secondary myelofibrosis.
They are also found in malignant infiltrative disorders of the bone marrow .
Dacryocytes have rarely been described in blood smears from patients with autoimmune hemolytic anemia (AIHA) and microangiopathic anemia (MAHA). The clear prevalence of dacryocytes in AIHA and MAHA is unknown.
When evaluating patients with leukoerythroblastic smears (defined by the presence of myeloid forms and early erythroids), the presence of tear cells may be helpful in distinguishing often malignant marrow infiltrative conditions from a benign reactive process.
Conditions in which tear cells are seen with high frequency can also have extramedullary hematopoiesis, particularly in the spleen.
These tear cells correspond to abnormal red blood cells with a single point of elongation. They occur in different types of anemia and are particularly characteristic of megaloblastic anemia, bone marrow metastases, and myelofibrosis.
Mechanism of dacryocyte formation
The mechanism of dacrocyte or tear cell formation may be multifactorial, but appears to involve distortion of red blood cells as they pass through the bone marrow or splenic sinusoids.
Tear cells resulting from conditions such as metastatic bone marrow cancer probably primarily involve a medullary origin of the cells, whereas primary myelofibrosis with prominent extramedullary hematopoiesis includes a splenic mechanism of tear cell formation.
“In general, the absolute Average Platelet Volume count and its indexes appear in the final portion of the hemogram reports that are issued by the Clinical Laboratories.”
Megaloblastic anemia is a type of anemia, a blood disorder in which the number of red blood cells is lower than normal.
Red blood cells carry hemoglobin, an iron-rich protein that binds to oxygen in the lungs and carries it to tissues throughout the body. Anemia occurs when you do not have enough red blood cells or when your red blood cells do not work properly.
It is diagnosed when a blood test shows a hemoglobin value of less than 13.5 gm / dl in a man or less than 12.0 gm / dl in a woman. Normal values for children vary with age.
When you have anemia, your body is starved of oxygen, so you may experience one or more of the following symptoms:
- Soft spot.
- Short of breath.
- Fast or irregular heartbeat
- Knocking or “whistling” in your ears.
- Cold hands or feet
- Pale or yellow skin
- Chest pain.
Other diseases associated with the presence of dacryocytes
In this disorder, myeloid cells proliferate like crazy right from the start. If you were to look at the blood and bone marrow at this early stage, you would see a high white count with a left shift and hypercellular marrow, features common to all myeloproliferative disorders.
But as the disease progresses, the marrow is replaced by fibrous tissue. Hematopoietic precursors have nowhere to grow, so they begin to settle outside the marrow, in places like the liver and spleen.
The spleen, in particular, becomes massive, even larger than in other chronic myeloproliferative disorders.
You can see evidence of spinal fibrosis and splenomegaly in the blood by looking closely at the red blood cells. By squeezing through tight fibrosis in the marrow, and navigating through a markedly enlarged, cellular spleen, red blood cells take on an unusual “tear” shape.
You can almost see how they crawled through tight spaces, stretching their poor little bodies into elongated, pinched shapes.
Bone metastases are not the same as cancer that begins in the bone. Cancer that begins in the bone is called primary bone cancer. There are different types of primary bone cancers, such as osteosarcoma.
A tumor that has metastasized to bone is not made of bone cells. Bone metastases are made up of abnormal cancer cells that started from the original site of the tumor.
For example, lung cancer that spreads to the bone is made from lung cancer cells. In this case, the bone metastasis would be called metastatic lung cancer. In adults, metastatic bone cancer is much more common than primary bone cancer.