Primary polypeptide hormones and mucin-producing malignant carcinoid of the larynx

A case of primary malignant laryngeal carcinoid with dual endocrine and mucous differentiation is reported. Histologically the tumor showed a characteristic organoid pattern and exhibited Alcian-blue, periodic acid-Schiff, and Grimelius silver positivity. By the immunoperoxidase technique calcitonin, ACTH, and alpha-hCG subunit were demonstrated in the tumor cells. Electron microscopy revealed two different types of endocrinelike cells: mucous cells and occasional cells containing both endocrinelike granules and mucin droplets. Diagnostic morphologic criteria of this rare tumor entity are discussed and reference to biologic behavior and possible histogenesis is made.