Primary Small Cell Neuroendocrine Carcinoma of Paranasal Sinuses
Figure 4
Hematoxylin and eosin staining showing nasal mass with small cell carcinoma (a), immunohistochemical staining showing tumor positivity for AE1/AE3 in a dot-like pattern (b), synaptophysin (c), and high-risk HPV by in situ hybridization (d). (a) The tumor consisted of a uniform population of small cells with minimal cytoplasm and hyperchromatic, angulated nuclei that demonstrated molding. The tumor exhibited high grade features including a high mitotic rate and necrosis (hematoxylin and eosin, ×400). (b) The neoplasm was positive for cytokeratin on a perinuclear, dot-like pattern (AE1/AE3 immunohistochemistry, ×400). (c) The tumor exhibited neuroendocrine differentiation in the form of diffuse staining for synaptophysin (synaptophysin immunohistochemistry, ×400). (d) HPV studies showed that the tumor harbored high-risk HPV DNA (high-risk HPV in situ hybridization, ×400).
