Carcinoma of the larynx with mucosubstance production and neuroendocrine differentiation: an ultrastructural and immunohistochemical study.

Primary neuroendocrine tumors of the larynx appear to be extremely rare. We report a case of well-differentiated neuroendocrine carcinoma arising in the larynx of a 61-year-old white woman. This case was initially diagnosed as a lymph node metastasis in the neck from an unknown primary carcinoma. Extensive workup subsequently revealed that the larynx was the primary site of the tumor. An electron microscopic study of both the primary and metastatic tumors showed numerous neurosecretory-type granules. Immunohistochemical studies revealed positive immunoreactivity against calcitonin, somatostatin, and ACTH. However, the tumor also displayed focal exocrine differentiation and mucosubstance production. The patient underwent a supraglottic laryngectomy and radical neck dissection and was free of tumor 22 months postoperatively.