Two additional cases of parotid neuroendocrine carcinoma: Is there a wall that cannot be overcome in the cellular morphology?

Abstract

Herein, we summarize two rare cases of salivary neuroendocrine carcinoma arising in the parotid gland. The patients were a 54-year-old Japanese female and a 74-year-old Japanese male. In the first case, the tumor presented as a typical small cell carcinoma with extensive crush artifacts and nuclear molding, but metastatic foci of the lymph node revealed characteristic ribbon-like trabecular arrangements or sheet-like solid growths of tumor cells with moderate amounts of pale eosinophilic cytoplasm intermingled with bizarre giant or multinucleated cells. In the second case, the tumor was initially diagnosed as a small cell neuroendocrine carcinoma, but a retrospective review revealed that the large cell component was dominant and that it should be strictly considered a mixed large and small cell neuroendocrine carcinoma. The difference in prognoses between these two salivary subtypes remains unknown, and distinction between the small and large cell subtypes of neuroendocrine carcinomas seems merely simple and convenient in the salivary glands.