Fig. 3From: Primary malignant melanoma of the esophagus successfully treated with nivolumab: a case reporta Resected specimen showing an irregular elevated black lesion in the lower esophagus. b Hematoxylin–eosin staining of tumor cells. There was solid proliferation, and tumor cells had large round nuclei. Melanin pigmentation was sparse. c HMB-45 immunostaining. Tumor cells were diffusely positive. d Melan-A immunostaining. Tumor cells were diffusely positiveBack to article page