Pure red cell aplasia (PRCA) represents one of the most common paraneoplastic syndromes in patients with advanced thymoma. Ciclosporin is a very effective treatment in this condition, and it seems to have also a direct anti-cancer effect. We provide a case of radiological response of thymoma associated with the total absence of response of PRCA in a patient treated with ciclosporin. A 60-year-old man with advanced thymoma underwent first-line chemotherapy, achieving a partial disease response followed by 2 years of stable disease. After disease progression, the patient developed a PRCA, later expanded to platelets, and then he started therapy with ciclosporin, without any blood improvement. The CT revaluation after three months of ciclosporin therapy showed tumor shrinkage, although the inefficacy in the treatment of PRCA. The paper reports a case of dissociation between oncological and hematological response in a patient with thymoma-related PRCA, suggesting that the pathology of this condition deserves novel investigations. Further studies should be conducted to acquire more exhaustive knowledge and permit the integrated treatment of oncological and hematological conditions.