Fig. 6

Pseudoprogression demonstrated on magnetic resonance imaging (MRI). MRI axial T1 post-contrast fat saturation (FS) axial demonstrates: (A) baseline perineural spread from cutaneous squamous cell carcinoma (CSCC) with mass enhancement at left pons and cisternal portion of the left trigeminal nerve. B < 5 months, on immunotherapy, enlarged mass-like change in the left trigeminal nerve with increased enhancement at the left pons and left Meckel’s cave. C > 10 months, (26 months) post immunotherapy, the left pons mass has resolved and the thickening and enhancement of the left trigeminal nerve has resolved