How would you work up splenomegaly and abdominal pain in a patient with primary antiphospholipid syndrome and a high + ANA, but no other serological or clinical SLE symptoms?   

20 yo pt with APS (triple positive, DVT and PE, on warfarin for years). Known high + ANA but all other serologies negative. No cytopenias. No other APS or SLE symptoms since diagnosis years ago. Chronic abdominal pain. On abdominal US found to have splenomegaly at 15cm, normal liver and normal US otherwise.