A patient presents with painful oral ulcers and tender submandibular, anterior cervical, and posterior cervical lymphadenopathy. Which condition is most likely associated with this presentation?

Behçet's syndrome is a systemic vasculitis characterized by recurrent oral ulcers, genital ulcers, uveitis, and skin lesions. Oral ulcers in Behçet's syndrome are similar to aphthous ulcers but are part of a multisystem disease. The involvement of multiple cervical lymph node chains (submandibular, anterior, and posterior cervical) combined with painful oral lesions suggests a systemic inflammatory condition. Behçet's disease is diagnosed clinically using the International Study Group criteria, which require recurrent oral ulcers plus at least two of the other manifestations. Infectious mononucleosis (EBV) would also produce posterior cervical lymphadenopathy but typically presents with pharyngitis, fatigue, and splenomegaly.