How would you approach the evaluation and management of a patient with rheumatoid arthritis receiving leflunomide who presents with progressive peripheral pulmonary cavitary nodules, with biopsy revealing necrotizing granulomatous inflammation?

Given the association between leflunomide and nodules with necrosis and giant cells (though quite rare), I would consider stopping leflunomide and moving to another agent. I would, of course, make sure that cultures are negative on those nodules, given it could be mycobacterial, fungal, or even GPA.