PMC9868692_01
PMC9868692_02
PMC9868692_03
PMC9868692_04
Electronic nasopharyngoscopy reveals a neoplasm in the right nasal cavity (A, B). The fluorodeoxyglucose PET/CT scan may show multiple high metabolic signals in the nasal cavity (C) and cervical lymph nodes (D), suggesting the nasal cavity neoplasm growth and lymph node metastasis.
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In addition, FDG-PET/CT showed focal hypermetabolism of a soft-tissue mass in the nasal cavity, suggesting a malignant tumor lesion (Figures 1C, D).
The histopathological appearance of this neoplasm suggests a high-grade round cell malignant tumor, which is consistent with ONB (Hyams grade: IV). The tumor is composed of uniform small round cells that form irregular clusters or islands against a background of hyperplastic vascular and fibrous stroma. The nuclei of the small cells are round or oval, dark stained, uniform in size, and have high mitotic activity. The cytoplasm is stained pink [(A, B), H and E staining]. Immunohistochemistry shows tumor cells are positive for S-100 (C), CD56 (D), chromogranin (E), synaptophysin (F), neuron-specific enolase (G), and pan-cytokeratin (H). The S-100 protein positive cells are located at the periphery of the tumor lobule (C). CD56 gives strong and obvious membrane-type staining in some tumor cells (D). Chromogranin yields a different granular reaction in the cytoplasm of the neoplastic cells (E). Synaptophysin immunoreactivity is positive in partial tumor cells (F). Part of the tumor cells are positive for neuron-specific enolase in the cytoplasm (G). Pan-cytokeratin staining shows dot-like strongly positive expression (H). (A) Original magnification x 200; (B-G) original magnification x 400.
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Hyams, ONB could be divided into four grades (Table 1). HE staining of this patient presented obvious mitotic figures, significant nuclear pleomorphism, and lack of typical lobular structure, meeting the diagnostic criteria of Hyams grade IV (Figures 2A, B). CD56, chromogranin, synaptophysin, neuron-specific enolase, and pan-cytokeratin (Figures 2C-H). CD99,