Although there has been considerable advancement in treatment techniques but still there are some illnesses that continue to exhibit a rather poor curability, such as thymoma. This report highlights the benefit of octreotide and prednisolone therapy in a 15-year-old girl, who was diagnosed with inoperable thymus carcinoma, with chemotherapy and radiotherapy being the last resort. The detection of type 2 somatostatin receptors on the surface of the tumor justified the introduction of treatment with somatostatin analog and prednisolone. Fortunately, after 6 months of this treatment, the tumor showed partial regression. However, 2 months later, somatostatin receptor negative metastases appeared; therefore, a switch over to imatinib became essential, because the tumor was CD-117 positive. Despite the therapy change, the patient's condition deteriorated owing to tumor progression.