This CSF slide came from a patient suffering from viral meningitis. Notice the absence of neutrophils and the large numbers of lymphocytes, most of which are normal.
There is more cytoplasm in the three atypical lymphocytes indicated by the arrows than in normal lymphocytes. These atypical lymphocytes have chromatin patterns similar to mature lymphocytes, even though the cells have increased size.
As a lymphocyte becomes more activated in response to a viral infection, it is more likely that nucleoli will be present on a cytospin, especially in the pediatric population.
Nucleoli alone do not make an atypical lymph malignant or leukemic. Chromatin textures and cytoplasmic volumes will be altered as well in leukemia and lymphoma.