Teardrop-shaped cells, medically known as dacryocytes, are red blood cells that resemble a tear or a pear. Their distinctive appearance, tapering at one end and rounded at the other, makes them easily identifiable under a microscope. Their presence in the bloodstream signals potential underlying health issues that warrant further investigation.
Understanding Teardrop Cells
When viewed under a microscope, teardrop cells have an elongated, pear-like, or tadpole-like shape, with a rounded body and a blunt projection. This is unlike healthy red blood cells, which are normally biconcave discs. Teardrop cells form when red blood cells are forced to squeeze through an abnormal or stiffened bone marrow. This mechanical stress distorts their shape as they exit the marrow and enter the bloodstream.
The process can also involve red blood cells with internal inclusions attempting to pass through narrow microcirculation, causing parts of the cell to pinch off. This distortion results in the characteristic tailed appearance. These cells are observed through a microscopic examination of a peripheral blood smear. Their presence often indicates changes in the bone marrow’s structure.
Key Conditions Associated with Teardrop Cells
Teardrop cells in a peripheral blood smear indicate potential bone marrow abnormalities. They are associated with conditions that alter bone marrow architecture, especially those involving fibrosis. Myelofibrosis is the most common condition where teardrop cells are prominently observed.
Myelofibrosis is a chronic bone marrow disorder characterized by excessive fibrous, scar-like tissue buildup within the bone marrow. This fibrosis displaces normal blood-producing cells, leading to a crowded and rigid environment. Red blood cells navigating this dense, fibrotic marrow are mechanically squeezed and distorted into their teardrop shape. Teardrop cells are often accompanied by nucleated red blood cells and immature white blood cells in the peripheral blood, known as leukoerythroblastosis. This suggests the bone marrow struggles to produce blood cells effectively, sometimes leading to blood cell production in other organs like the spleen, a process called extramedullary hematopoiesis.
Teardrop cells also appear in other myeloproliferative neoplasms (MPNs), disorders where the bone marrow produces too many red blood cells, white blood cells, or platelets. These include essential thrombocythemia (ET) and polycythemia vera (PV), particularly if they progress to a fibrotic phase. Genetic mutations, such as in JAK2, CALR, or MPL genes, drive abnormal cell proliferation in these conditions, leading to bone marrow scarring. While MPNs can present with teardrop cells, their prominence is highest in myelofibrosis.
Beyond myeloproliferative disorders, teardrop cells can appear in other severe anemias, though their diagnostic significance differs. Conditions like thalassemia, an inherited blood disorder affecting hemoglobin production, can show teardrop cells. Severe iron deficiency anemia, where the body lacks sufficient iron to make healthy red blood cells, may also feature these cells. In these anemias, teardrop cell formation may involve different processes, such as abnormal red blood cell maturation or changes related to splenic function, rather than extensive bone marrow fibrosis. While their presence in anemias warrants attention, it does not carry the same diagnostic weight as in myelofibrosis.
The Diagnostic Process and Next Steps
The identification of teardrop cells on a peripheral blood smear prompts further medical investigation. These cells indicate an underlying condition affecting the bone marrow or blood cell production. However, they do not provide a definitive diagnosis alone.
After initial observation, a healthcare provider recommends additional diagnostic procedures to determine the cause. A bone marrow biopsy is a subsequent step, providing a direct sample for detailed examination of cellularity, fibrosis, and abnormal cells. Genetic testing is also performed for mutations in genes like JAK2, CALR, and MPL, associated with myeloproliferative neoplasms. Other blood tests include a complete blood count with differential and a comprehensive metabolic panel. A comprehensive evaluation of all findings helps pinpoint the specific condition and formulate an appropriate treatment plan.