Fig. 1

The image changes before and after treatment. The CT scan before treatment showed the mass in the right upper lobe sized 4.6 × 3.2 cm (a), mediastinal 4R enlarged lymph nodes (b). Contrast enhanced MRI of brain before treatment revealed multiple intracranial space-occupying lesions (c). The CT examination after treatment with pralsetinib displayed the mass sized 2.8 × 1.2 cm in the right upper lobe (d), marked reduction in the size of lymph node in mediastinum 4R (e). Brain MRI after treatment demonstrated the shrink of the right parieto-occipital region (f). Red arrows indicate the tumor or lymph node lesions