High-Grade Neuroendocrine Carcinoma Within a Tracheal Polyp: A Case Report

Abstract

Introduction: Primary carcinomas of the trachea are rare, with a reported annual incidence of one in a million. We present a case of a previously undescribed polypoid high-grade neuroendocrine carcinoma of the trachea. Resection of the carcinoma revealed only superficial invasion of the mucosa and without evidence of local or distant metastatic disease. Histologically, the tumor had high-grade features with necrosis and a high mitotic index. Methods: Characterization of this rare neuroendocrine carcinoma of the trachea was performed by immunohistochemistry and whole-genome sequencing. Results: Immunohistochemistry result was positive for neuroendocrine markers, p16 and an elevated Ki-67. Whole-genome sequencing of the lesion was performed and revealed a very unusual and very distinct mutational signature without relationship to other relevant neuroendocrine carcinomas. Neither known driver nor targetable mutations were found by whole-genome sequencing. Analysis of the sequence of numerous viral elements of human papillomavirus-18 suggests that the pathogenesis of the lesion is related to viral integration. The patient developed distal recurrence, which progressed to widespread pulmonary dissemination, presumably through aerogenous spread of disease. Conclusions: This is the first characterization of this type of tracheal tumor, including genomic findings, pathogenesis, and natural history.

Keywords

• Neuroendocrine carcinoma/tumor
• Tracheal tumor
• Whole-exosome sequencing
• Case report