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Teardrop cells

From www.haematologyetc.co.uk


also known as dacrocytes


Derivation: Descriptive (teardrop)



Appearance

The abnormal cells have the shape of a teardrop.


Image 1 Teardrop cell The classic form is sometimes described as having a “pinched top” but the resemblance to a tear drop is probably the best description. Note that the cell is otherwise a normal erythrocyte, so central pallor is generally retained and that other abnormal features (e.g. basophilic stippling, crenation, hypochromia) may all also occur. The teardrop cell is generally accompanied by other features of infiltration e.g. polychromasia, circulating nucleated red cells. There may also be other features of the primary underlying pathology.



Significance

The teardrop appearance is strongly indicative of a “packed marrow”. This may be the result of infiltration by a disease process: e.g. fibrosis (primary or secondary) or neoplasm (carcinoma or haematological neoplasm). However, these cells may also arise where there is a sustained or marked physiological increase in blood cell production (e.g. the expanded erythroid response to thalassaemia). Other features suggesting infiltration or disease will generally be present, as may features suggesting a specific cause. Less frequent teardrop forms may arise in other systemic disease (see causes).


Pitfalls

Teardrop cells have a distinctive appearance and so while they may superficially resemble elliptocytes or ovalocytes, they are not usually confused with other cell types. The major point of importance is to make a careful examination of other cells that may provide clues as to why teardrop forms are present.




Intrinsic bone marrow disease
Primary myelofibrosis: often associated with frequent teardrop forms – look for other features of infiltration and characteristic changes to other blood cells.
Secondary marrow fibrosis (including carcinoma and TB; rarely congenital conditions)
Haematological malignancy – abnormal white cells will generally be present.
Packed or extramedullary red cell formation
Predominantly thalassaemia, but also may occur in a range of haemoglobinopathies
Particular dyserythropoietic disease states
Megaloblastic anaemia and myelodysplasia



Clinical Image 1 Very frequent teardrop forms (including a very small one – centre overlying other cells). This is caused by myelofibrosis. The diagnosis cannot be made from this small field, but note very high frequency of teardrop forms that may be typical of this condition. Clinical condition: myelofibrosis.


Clinical Image 2: Poorly-formed but recognisable teardrop cell amongst many abnormal erythrocytes and hypogranular platelets. Note also the bi-lobed (pseudo-Pelger) neutrophil. This is myelodysplasia with occasional teardrop cells. Clinical condition: myelodysplasia.


Clinical Image 3: A single well-formed teardrop cell. However, in this case there is also a primitive (blast) cell and a basophil present. Platelets also appear greatly increased. The condition is again myelofibrosis although the circulating blast cell should raise concern about possible transformation. Clinical condition: myelofibrosis.


Pathobiology

The precise mechanism by which teardrop cells are formed is uncertain. There is a view that the cells represent the result of erythropoiesis occurring outside the normal marrow adhesive environment, although the “pitting function” of the spleen may also play a role in their formation.