Complex sentence: Cervical lymphadenopathy is seen in 50 to 75% of patients, whereas the other features are estimated to occur in 90% of patients, but sometimes it can be the dominant presenting symptom.
Split into simpler sentences: Cervical lymphadenopathy is seen in approximately 50 to 75% of patients, whereas the other features are estimated to occur in 90% of patients. But sometimes it can be the dominant presenting symptom.