Collision tumor of squamous cell carcinoma and neuroendocrine carcinoma in the head and neck: A case report

Figure 1 Images before surgery showing a mass in the nasal cavity and paranasal region.

Figure 2 Immunohistochemical images. A: Hematoxylin and eosin (HE) staining showed typical squamous and neuroendocrine differentiation areas of the neoplasm; B: CK5/6 was diffusely positive in the squamous differentiation area and negative in neuroendocrine differentiation cells; C: P40 was diffusely positive in the squamous differentiation area; D: CD56 was positive in neuroendocrine components; E: Chromogranin A expression was negative; F: Synaptophysin expression was negative. Original magnification, × 200.

Figure 3 The patient has a complete response after chemoradiotherapy. A: Images after surgery showing postoperative residual lesions (orange arrows); B: Images after surgery showing that a complete response was achieved; C: The latest positron emission tomography-computed tomography showing no signs of recurrence or metastasis.