What is the significance of teardrop cells (dacrocytes) on the peripheral smear of my patient with newly-discovered pancytopenia?

The presence of teardrop cells (dacrocytes) (Figure below) in the peripheral blood, named for their tear drop shape, is a prominent feature of myelophthisic (marrow infiltrative) conditions, including myelofibrosis, hematologic malignancies, cancer metastatic to the bone marrow, and granulomatous diseases. Teardrop cells may also be seen in beta-thalassemia, autoimmune and microangiopathic hemolytic anemia and severe iron deficiency (1-4).

 
When evaluating patients with leucoerythroblastic smears (defined by the presence of early myeloid and erythroid forms), the presence of teardrop cells can be helpful in distinguishing often malignant marrow infiltrative conditions from a benign reactive process.  Conditions where teardrop cells are seen with high frequency may also have extramedullary hematopoiesis, particularly in the spleen (1,2).

 
The mechanism of tear drop cell formation may be multifactorial but appears to involve distortion of the red cells as they pass through marrow or splenic sinusoids. Teardrop cells resulting from conditions such as cancer metastatic to the bone marrow likely involve primarily a marrow origin of the cells whereas primary myelofibrosis with prominent extramedullary hematopoiesis include a splenic mechanism of tear drop cell formation (2).

 
Supporting the possible splenic contribution to teardrop cell formation is the observation that teardrop cells may be reduced in number or eliminated entirely after splenectomy in patients with myelofibrosis and autoimmune hemolytic anemia (1,4).

Teardrop

Figure. Teardrop cells

References

1. DiBella NJ, Sliverstein MN, Hoagland HC. Effect of splenectomy on teardrop-shaped erythrocytes in agnogenic myeloid metaplasia. Arch Intern Med 1977; 137: 380-381. https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/586447
2. Gutgemann I, Heimpel H, Nebe CT. Significance of teardrop cells in peripheral blood smears. J Lab Med 2014; DOI: 10.1515/labmed-2014-0005 https://www.researchgate.net/publication/272430111_Significance_of_teardrop_cells_in_peripheral_blood_smears
3. Korber C, Wolfler A, Neubauer M, Robier Christoph. Red blood cell morphology in patients with β-thalassemia minor. J Lab Med 2016-12-10 | https://www.researchgate.net/publication/311564128_Red_blood_cell_morphology_in_patients_with_b-thalassemia_minor DOI: https://doi.org/10.1515/labmed-2016-0052
4. Robier C, Klescher D, Reicht G,Amouzadeh-Ghadikolai O, Quehenberger F, Neubauer M. Dacrocytes are a common morphologic feature of autoimmune and microangiopathic haemolytic anaemia. Clin Chem Lab Med. 2015;53:1073-6. https://www.ncbi.nlm.nih.gov/pubmed/25503671

Contributed by Tom Spitzer, MD, Director of Cellular Therapy and Transplantation Laboratory,  Massachusetts General Hospital, Boston, MA.
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What is the significance of teardrop cells (dacrocytes) on the peripheral smear of my patient with newly-discovered pancytopenia?

Can native valve infective endocarditis be associated with hemolytic anemia?

Yes, but it’s rare!  Hemolytic anemia (HA) in the setting of infective endocarditis (IE) has only been described in a few case reports (1-3).  Although diseased valves may cause shearing stress that fragments RBCs, similar to that associated with mechanical heart valves, an autoimmune hemolytic process has also been implicated. 

A 2018 case report describes a patient with hypertrophic obstructive cardiomyopathy (HOCM) with left ventricular outflow tract (LVOT) obstruction who had HA secondary to subacute IE due to Actinomyces israelii (1).   The anemia completely resolved after treating the IE (1). The cause was most likely mechanical shearing (schistocytes or fragmented RBCs present on peripheral smear) by the diseased valves; autoimmune hemolysis was considered unlikely in this case due to consistently negative Coombs tests and failure to respond to corticosteroids (1). 

An autoimmune mechanism was invoked by a 1999 report reviewing 6 cases of HA associated with IE (3).  All patients had fragmented erythrocytes, but several also demonstrated an immune-mediated mechanism for their HA, supported by the presence of spherocytes, splenomegaly, and + Coombs test (2,3).  The production of anti-erythrocyte antibodies, modification of antigenicity of erythrocyte antigens, or unmasking of antigens in IE may play a role (1,3). Additional evidence in support of an immune-mediated mechanism of HA in IE has been provided by an experimental study demonstrating significantly shorter RBC half-life in rabbits with intact spleen compared to that of splenectomized animals (4).

 

References

1. Toom S, Xu Y. Hemolytic anemia due to native valve subacute endocarditis with Actinomyces israellii infection. Clin Case Rep 2018;6: 376-79. https://onlinelibrary.wiley.com/doi/epdf/10.1002/ccr3.1333 

2. Hsu CM, Lee PI, Chen JM, et al. Fatal Fusarium endocarditis complicated by hemolytic anemia and thrombocytopenia in an infant. Pediatr Infect Dis 1994;13:1146-48. https://www.ncbi.nlm.nih.gov/pubmed/7892087 

3. Huang HL, Lin FC, Hung KC, et al. Hemolytic anemia in native valve infective endocarditis. Jpn Circ J 1999;63:400-403. https://www.ncbi.nlm.nih.gov/pubmed/10943622 

4. Joyce RA, Sand MA. Mechanism of anaemia in experimental bacterial endocarditis. Scand J Haematol 1975;15:306-11. https://www.ncbi.nlm.nih.gov/pubmed/1198067 

 

Contributed by Scott Goodwin, Medical Student, Harvard Medical School, Boston, MA. 

 

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Can native valve infective endocarditis be associated with hemolytic anemia?