Neuroendocrine carcinomas of the larynx: what do the different histologic types really mean?

Abstract

A century ago, it was a signiWcant accomplishment to distinguish between laryngeal epithelial malignancies (carcinomas), mesenchymal malignancies (sarcomas) and hematopoietic malignancies (lymphomas). A great deal has changed since that time; while the vast majority of laryngeal malignancies will prove to be carcinomas, the family of carcinomas has grown to encompass an impressively large array of diVerent pathologically deWned entities. One subset of epithelial malignancies of the larynx that can give rise to some confusion is one of the more uncommon subsets, the group of neuroendocrine carcinomas of the larynx. To be clear, this group—to be discussed here— comprises the epithelial-derived neuroendocrine tumors, and so excludes the neurally derived tumors (such as paraganglioma, neuroblastoma, Ewing’s sarcoma, and primitive neuroectodermal tumor). As such, this group of epithelial neuroendocrine carcinomas of the larynx encompasses four discrete pathologically deWned entities: carcinoid tumor, atypical carcinoid tumor, small cell neuroendocrine carcinoma, and large cell neuroendocrine carcinoma (as well, combined tumors—such as atypical carcinoid tumors, small cell and large cell neuroendocrine carcinomas—may be encountered, but are not further discussed here in light of their extreme rarity) [1–4]. While these four tumor types are marked by widely diVering light microscopic appearances, they are united by the presence of some combination of positivity by immunohistochemistry with antibodies including cytokeratin, chromogranin, synaptophysin, CD56, CD57, neuron-speciWc enolase, serotonin, somatostatin, bombesin, and protein gene product 9.5 [5].