Question

What is lymphocytosis when does it occur?

Answer 1

Causes. You may have a lymphocyte count that is higher than would normally be expected but have few, if any, symptoms. It's usually a harmless, temporary situation, as can occur after an illness. But it may represent something more serious, such as a blood cancer or a chronic infection.

Answer 2

It is abnormal increase in lymphocyte count.
It may be due to cancer or any other cause.