Fig. 4

Macroscopic and microscopic images of a 73-year-old man with extramammary Paget’s disease. a External appearance before boron neutron capture therapy (BNCT): a pruritic, painful and persistent erythematous lesion (arrows) was on the perianal region and scrotum. b Microscopic findings: the histopathologic findings showed large, ovoid, infiltrating malignant epithelial cells with abundant cytoplasm, round nuclei and prominent nucleoli. c External appearance after BNCT (early reaction): BNCT delivered an absorbed dose of 7.3 Gy-Eq to the normal skin and 18 Gy-Eq to the tumor. The most severe adverse event in normal skin was erosion during the first 2 months, which was subsequently resolved with skin medication. d External appearance after BNCT (late reaction): he had a complete response with depigmentation of the lesion, and was alive and well without evidence of recurrence or adverse effects for 6.5 years after BNCT