Non-Hodgkin lymphoma is caused by abnormal white blood cells. While there are several types, non-Hodgkin lymphoma can be divided into slow-growing and fast-growing subtypes. 

Follicular lymphoma is the most commonly diagnosed slow-growing lymphoma. Under a microscope, follicular lymphoma looks like a can of worms, which is where the subtype gets its name.  

Paolo Strati, M.D., answers seven questions about follicular...