Content continues after advertisement

Hemophagocytosis in Cats

Anne M. Barger, DVM, MS, DACVP, University of Illinois

Clinical Pathology

|November 2019

Sign in to Print/View PDF

In the Literature

Schaefer DMW, Rizzi TE, Royal AB. Hemophagocytosis and Histoplasma-like fungal infection in 32 cats. Vet Clin Pathol. 2019;48(2):240-254.


Hemophagocytosis is the macrophage phagocytosis of blood cells, including erythrocytes, leukocytes, platelets, and their precursors. Depending on the cell type phagocytized, hemophagocytosis can be further described as erythrophagia (ie, phagocytosis of RBCs) or leukophagia (ie, phagocytosis of WBCs). Hemophagocytosis can occur as a way to eliminate old and dying cells or, in the case of erythrophagia, may indicate hemorrhage. In some cases, however, the presence of hemophagia in the absence of hemorrhage or aging cells raises concern for a more severe underlying disease process (eg, neoplasia, immune-mediated disease, significant inflammation). There have only been a few reports of inappropriate hemophagocytosis in cats1,2; therefore, identification of erythrophagia, particularly in the absence of obvious hemorrhage, is concerning.

Hemophagocytic syndrome—referred to in humans as hemophagocytic lymphohistiocytosis—is a rare disease that can be familial or acquired.3 This syndrome is the result of overreactive T cells, macrophages, and other histiocytic cells and can result in peripheral cytopenias. In humans, it has been reported to accompany various infectious organisms, including viruses, Toxoplasma gondii, and Cryptococcus spp4; in such cases, patients are frequently immunosuppressed.4

In the present case series report, the authors describe 32 cats infected with Histoplasma spp-like organisms that had accompanying hemophagia noted on cytology. Many of these cats also had concurrent cytopenias, which may or may not have been the result of hemophagocytosis. This is an important sequela to consider if a patient has cytopenia associated with an infectious disease that does not correct when the infection is appropriately treated. Erythrophagia has been reported previously in cats with neoplasia and immune-mediated disease but has not commonly been reported to be associated with an infectious organism. In the single case report of feline hemophagocytic syndrome identified in the literature, the cat was FIV positive.2 These results suggest that fungal infection may be another important differential if hemophagia is noted on cytology or histopathology.

Cytospin preparation of a hemorrhagic effusion from a dog. Erythrophagia (one represented by the arrow) can be noted in several macrophages.

FIGURE Cytospin preparation of a hemorrhagic effusion from a dog. Erythrophagia (one represented by the arrow) can be noted in several macrophages.


Key pearls to put into practice:


Hemophagia is a nonspecific pathologic finding associated with inflammation or hemorrhage or may be indicative of underlying immune-mediated, infectious, or neoplastic disease.



Systemic fungal disease should be considered as a differential when hemophagia is noted on a feline cytologic sample.


For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


Clinician's Brief:
The Podcast

Listen as host Beckie Mossor, RVT, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Privacy Policy (Updated 05/08/2018) Terms of Use (Updated 05/08/2018)