Laryngeal neuroendocrine tumour with features of a paraganglioma, intracytoplasmic lumina and acinar formation.

A supraglottic laryngeal neuroendocrine tumour in a 71-year-old female is presented. In addition to the typical features of extra-adrenal paragangliomas it showed unusual, numerous intracytoplasmic lumina and occasional true acini with accumulation of alcian blue and PAS positive secretory product in them which led originally to an erroneous diagnosis of metastatic adenocarcinoma. Ultrastructurally, the tumour was composed of light and dark chief cells containing varying numbers of dense-core secretory granules. Intracytoplasmic lumina and true acini contained microvilli with glycocalyceal material and varying amounts of membranous and amorphous material, possibly secreted via small, smooth-surfaced cytoplasmic vesicles but typical mucin granules were not seen. These features have not been previously described in laryngeal paragangliomas but are seen in endocrine tumours of other sites and have been used as an argument in favour of an endodermal rather than ectodermal origin for endocrine cells in those sites. Laryngeal paragangliomas are often malignant and the presence of spasmodic pain appears to be the most reliable indication of possible malignancy, histological criteria being as yet poorly defined.