Teardrop cells, also known as dacryocytes, are red blood cells with an unusual, elongated shape resembling a teardrop or a pear. Their distinctive morphology is observed during the microscopic examination of a peripheral blood smear, a routine laboratory test. While their presence often signals underlying medical conditions, not every instance indicates a severe disease. This article clarifies what teardrop cells are, when their appearance might be expected, and the medical contexts in which they are found.
Understanding Teardrop Cells
Teardrop cells are a type of poikilocyte, a general term for abnormally shaped red blood cells. They are identified by laboratory professionals examining a peripheral blood smear under a microscope.
Their formation often occurs when red blood cells are forced to navigate through a compromised bone marrow environment. This can involve mechanical squeezing as cells exit a fibrotic or infiltrated bone marrow, or it may result from the spleen’s attempts to “pit” or modify red blood cells containing inclusions, leading to their deformation. True teardrop cells have blunt tips and point in different directions, distinguishing them from artifacts of smear preparation where points are sharp and uniform.
When Teardrop Cells Are Expected
While commonly associated with certain medical conditions, teardrop cells can sometimes be found in less concerning or even benign contexts. A very small number might occasionally be observed in otherwise healthy individuals, though this is rare and typically not clinically significant. Their presence becomes more noteworthy when consistently seen or in larger quantities.
Teardrop cells can be a transient finding in conditions like severe iron deficiency anemia, particularly before treatment. Similarly, megaloblastic anemia, resulting from deficiencies in vitamin B12 or folate, can also lead to their formation. In these situations, the underlying cause is often reversible with appropriate nutritional supplementation or treatment, and the teardrop cell morphology may resolve as the condition improves. Transient stress on the bone marrow, such as from certain severe anemias, can also lead to their appearance without necessarily indicating a chronic, severe pathology.
Medical Conditions Associated with Teardrop Cells
Teardrop cells are frequently a significant indicator of conditions affecting the bone marrow’s structure or function. The most common association is with myelofibrosis, a disorder where the bone marrow develops excessive fibrous scar tissue. Red blood cells are mechanically distorted as they attempt to squeeze through the narrowed and stiffened marrow spaces. Their presence in myelofibrosis is often accompanied by other abnormal findings, such as immature white and red blood cells in the peripheral blood, known as a leukoerythroblastic picture.
Other myeloproliferative neoplasms, like polycythemia vera or essential thrombocythemia, can also lead to teardrop cells, especially in later stages when bone marrow fibrosis may develop. Infiltrative bone marrow diseases, where the marrow is replaced by abnormal cells, can also cause teardrop cell formation. This includes metastatic cancers, certain hematologic malignancies, and granulomatous diseases.
Teardrop cells are also observed in severe forms of hemolytic anemias, where red blood cells are prematurely destroyed. This includes autoimmune hemolytic anemia and microangiopathic hemolytic anemia, where red cell membrane damage or passage through abnormal microcirculation can contribute to their shape. Thalassemias, genetic blood disorders affecting hemoglobin production, can similarly feature teardrop cells in more severe cases. Mechanisms may involve the spleen’s efforts to remove damaged cells or red cells passing through altered splenic microcirculation.
Interpreting Blood Test Findings
The identification of teardrop cells typically begins with a routine complete blood count (CBC) that may show abnormalities, prompting a more detailed examination of a peripheral blood smear. However, the presence of these cells alone is not sufficient for a diagnosis.
A healthcare professional will consider the entire clinical picture, including a patient’s symptoms, medical history, and other blood test results. For instance, a bone marrow biopsy may be necessary to assess the degree of fibrosis or infiltration when teardrop cells are present, especially if myelofibrosis is suspected. The proportion of teardrop cells can sometimes correlate with disease severity, making them a useful marker for monitoring. A comprehensive medical evaluation is always necessary to determine the underlying reason for teardrop cells and to guide appropriate treatment, given the wide range of potential causes.