A 52-year-old male patient, who lives in a countryside town and is a rural worker, presents with painful lesions in the oropharyngeal mucosa which have been growing for at least six months. He also complains of fatigue, loss of 10 kilos (approximately 22 lb), cough with mucus expectoration, dysphagia and odynophagia. He is only able to take in soft semi-solid food and liquids. On physical examination, it is observed enlarged, mildly soft and tender, well delimited, non-adherent and non-confluent cervical lymph nodes. Thirty days after beginning therapy with trimethoprim-sulphametoxazole, his symptoms improve considerably.

 

Question:
Based on the clinical history and images provided, which is the most likely diagnosis?