What does it mean to have abnormal lymphocytes with prominent nuclei and clumping on film for a blood test. and enlarged spleen. possible causes?

Many possibilities: Often associated with viral infections such as EBV disease it may also occur with non-infectious inflammatory conditions and with some hematologic malignancies. You do not provide enough info to go further than that, but a good clinical diagnostician should be able to work this out with further testing. Good luck and best wishes.