Peripheral Blood, Infectious mononucleosis [LMP78998]

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Image Details
Diagnostic Modality: 
Micrograph
Disease Category: 
Infectious Diseases
Diagnosis: 
Infectious mononucleosis
Species: 
Human
Organ System: 
Red Blood Cells and Bleeding Disorders
Gender: 
Female
Age: 
19 years
Diagnosis Code: 
ICD-10: B27.0
Slide Contributor Information
Hodgson, A. , Wang, C.

Keywords

Mono, EBV, atypical, lymphocytes, lymphocytosis, Gammaherpesviral mononucleosis

Clinical History

Presents to the emergency department with malaise - found to have a lymphocytosis, splenomegaly, hepatomegaly, and positive Heterophile antibody test.

Clinical Discussion

Infectious mononucleosis is a benign self-limited lymphoproliferative disorder caused by infection with Epstein-Barr virus (EBV). Symptoms typically include fever, sore throat, lymphadenopathy, splenomegaly, and characteristic atypical lymphocytes in the peripheral blood.

EBV is a herpes virus which infects B cells. Lytic infection can occur, however most infections are latent. Due to the function of several viral proteins, infected B cells begin to proliferate. The characteristic symptoms begin when the host immune response is initiated. Shown in this photograph are 4 atypical lymphocytes showing characteristic voluminous cytoplasm indented by surrounding red blood cells and an indented or folded nucleus. Cytoplasmic vacuolations and azurophilic granules may also be seen. These atypical lymphocytes are mainly CD8+ cytotoxic T cells but may also be CD16+ natural killer (NK) cells, and they act to eliminate infected B cells. These atypical lymphocytes are relatively distinctive in this disease and strongly suggest the diagnosis of infectious mononucleosis, especially in a young patient.