A dacrocyte (or dacryocyte) is a type of

poikilocyte Poikilocytosis is variation in the shapes of red blood cells. Poikilocytes may be oval, teardrop-shaped, sickle-shaped or irregularly contracted. Normal red blood cells are round, flattened disks that are thinner in the middle than at the edges. A ...

that is shaped like a teardrop (a "teardrop cell"). A marked increase of dacrocytes is known as dacrocytosis. These tear drop cells are found primarily in diseases with bone marrow fibrosis, such as: primary

myelofibrosis Primary myelofibrosis (PMF) is a rare bone marrow blood cancer. It is classified by the World Health Organization (WHO) as a type of myeloproliferative neoplasm, a group of cancers in which there is growth of abnormal cells in the bone marrow. ...

myelodysplastic syndrome A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may ...

s during the late course of the disease, rare form of acute

leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ' ...

s and myelophthisis caused by metastatic

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

s. Rare causes are myelofibrosis associated with post-irradiation, toxins, autoimmune diseases, metabolic conditions, inborn

hemolytic anemia Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonly ...

iron-deficiency anemia Iron-deficiency anemia is anemia caused by a iron deficiency, lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague such as Fatigue (me ...

β-thalassemia Beta thalassemias (β thalassemias) are a group of genetic disorder, inherited hemoglobinopathy, blood disorders. They are forms of thalassemia caused by reduced or absent synthesis of the HBB, beta chains of hemoglobin that result in variable out ...

Etiology

One theory regarding dacrocyte formation is that red blood cells containing various inclusions undergo "pitting" by the spleen to remove these inclusions, and in the process, they can be stretched too far to return to their original shape. It is also thought that this can similarly occur when red blood cells with large inclusions are obstructed from passing through the microcirculation, and the portion containing the inclusion thus gets pinched, leaving a tailed end. As dacrocytes are associated with myelofibrosis, they are also theorized to be formed due to mechanically squeezing out from the bone marrow as a result of the infiltrative process.

References

External links

* http://www.brown.edu/Courses/Digital_Path/systemic_path/heme/darocytes.html {{Abnormal clinical and laboratory findings Abnormal clinical and laboratory findings for RBCs