Fig. 2

Macroscopic findings, histopathological findings, and immunostaining findings of ARMM. a, b Pathological specimens revealed a semi-pedunculated tumor 30 mm in size in the anal canal and peripheral discontinuous melanin depositions. c Histopathological findings demonstrated diffuse proliferation of atypical cells with prominent nuclei of varying size accompanied by melanin depositions. d Positive for HMB-45. e Positive for S-100. f Positive for SOX-10