Combining anti-PD-1 antibodies with surufatinib for gastrointestinal neuroendocrine carcinoma: Two cases report and review of literature

Figure 1 Imaging examination, laboratory examination for cases. A: HE staining revealed poorly differentiated atypical cells with mixed large and small cells; the scale bar at the bottom right represents 1 cm. Immunohistochemistry of Syn, CgA, CD56 and ki-67; B: Pathological assessment of surgical tissue slides: HE staining revealed poorly differentiated ulcerous mixed neuroendocrine/neuroendocrine carcinoma (MiNEC), with a ratio of 30% poorly differentiated adenocarcinoma to MiNEC; C: Colonoscopy revealed a circumferential rectal neoplasm with an irregular shape; D: Computed tomography (CT) at diagnosis revealed irregular thickening of the rectal wall with uneven enhancement and multiple enlarged nodes in the pelvic cavity, abdomen, and left neck; E: PET/CT at diagnosis revealed hypermetabolic nodes in the pelvic cavity, abdomen, and left neck; F: CTs after 11 cycles of camrelizumab and surufatinib revealed partial remission; the sizes of both the primary rectal lesion and the lymph nodes had decreased (more than 30%); G: Dynamics of NSE during the treatment process.