Small-cell neuroendocrine carcinoma of the rectum — a rare tumor type with poor prognosis: A case report and review of literature

Figure 4 Postoperative histopathological analysis. A: Hematoxylin-eosin stain (× 40) showing a morphology of mainly small cells with a thick chromatin layer, scarce cytoplasm and no obvious nucleoli; B: Immunopositivity for CD56 (× 40); C: Immunopositivity for neuron-specific enolase (× 40); D: Ki-67 (80%) was positive (× 40).