Liver cyst on ct scan need biopsy?

Usually not: A liver cyst usually does not require a biopsy. Good documentation of the cyst and follow up will help to reassure. If follow up scan shows changes in character or growth, then a biopsy may be recommended at that point.

Almost certainly not: Provided it is a 'simple cyst' which is a fluid filled sac. Sometimes if there is debris or septations as cyst may be aspirated. If you are asymptomatic and the lesion is a simple cyst, it's best left alone.