Terminology and classification of neuroendocrine neoplasms of the larynx

OBJECTIVES

To review the history and literature on neuroendocrine neoplasms of the larynx and discuss the terminology and classification of these tumors.

STUDY DESIGN

Contemporary review.

METHODS

Published journal articles identified through PubMed and conference proceedings were reviewed.

RESULTS

Neuroendocrine neoplasms of the larynx include both epithelial (carcinomas) and neural-type lesions (paragangliomas).The nomenclature of these tumors has changed quite a bit over time, but recently, clearer categories have emerged that are biologically meaningful. They can overlap clinically and histologically so that segregation into the clinically relevant subtypes can be difficult, but it is extremely important to do so as they have a wide range of behaviors going from benign to rapidly fatal.

CONCLUSIONS

Neuroendocrine neoplasms of the larynx can be clearly categorized into the five tumor types: typical carcinoid, atypical carcinoid, small cell neuroendocrine carcinoma, large cell neuroendocrine carcinoma, and paraganglioma. These have concrete biologic and clinical significance and clearly dictate patient treatment.

Neuroendocrine neoplasms of the larynx: Advances in identification, understanding, and management

While 85-90% of laryngeal malignancies prove to be squamous carcinomas, the second most common tumour type found in the laryngeal region will prove to be a member of the family of neuroendocrine tumours. Laryngeal carcinoid tumours have a capacity for metastasis, and so are more aggressive tumours than their light microscopic features might imply--5-year survival rates are in the vicinity of 50%. Laryngeal atypical carcinoid tumours are lesions with a well-recognized capacity for local recurrence as well as metastasis, with a 5-year survival of just under 50%. Laryngeal small cell neuroendocrine carcinomas are particularly aggressive tumours, with a 5-year survival of no more than 5-10%. Laryngeal paragangliomas are lesions without any real capacity for metastasizing. Surgical excision is the mainstay of treatment of carcinoid tumours, atypical carcinoid tumours, and paragangliomas. Small cell neuroendocrine carcinomas are chiefly treated by way of radiation and chemotherapy; the role of adjuvant therapy in the treatment of atypical carcinoid tumours remains to be established.

Laryngeal mucosal malignant melanoma. A clinicopathologic, immunohistochemical, and ultrastructural study of four patients and a review of the literature

BACKGROUND

Primary laryngeal mucosal malignant melanomas are uncommon tumors that morphologically are readily confused with more common types of laryngeal cancer.

METHODS

Four cases of primary laryngeal mucosal malignant melanoma were identified from the files of the Otolaryngic Tumor Registry-Armed Forces Institute of Pathology. Clinical records were available for all four cases. Paraffin blocks or unstained slides were available for three of the four cases. The light microscopic features were evaluated in all cases. Immunohistochemistry was performed in three cases; electron microscopic analysis was performed in two cases. Follow-up data was available in three of the four cases.

RESULTS

The patients were all males and ranged in age from 35 to 84 years. The clinical presentations included hoarseness, hemoptysis, dysphagia, and airway obstruction, with complaints ranging from 1 to 8 months. The sites of involvement included the supraglottic larynx and the right true vocal cord. A history of cutaneous melanoma or of a melanoma of another site was not reported for any of the patients. Histologically, the tumors were invasive and composed of a pleomorphic epithelioid cell population of malignant cells. Malignant spindle-shaped cell could also be identified. The presence of melanin was identifiable by light microscopy in two cases; Fontana stains confirmed the presence of melanin in the other two. The immunohistochemical findings showed diffuse immunoreactivity with S-100 protein and HMB-45. There was no immunoreactivity with cytokeratin. The specimen of one patient demonstrated focal immunoreactivity with chromogranin. Electron microscopic features included the presence of premalonosomes or melanosomes. Total laryngectomy was the treatment of choice supplemented with radiotherapy. Follow-up information was available for three patients and all three died of metastatic disease within 36 months of diagnosis. Metastasis occurred to the brain, lungs, spine, and regional lymph nodes. The fourth patient was lost to follow-up.

CONCLUSIONS

Laryngeal mucosal malignant melanoma is an uncommon neoplasm that clinically and pathologically simulates more conventional types of laryngeal cancers. The light microscopic, immunohistochemical, and electron microscopic findings confirm the diagnosis. Aggressive management is indicated, as these tumors disseminate widely and are rapidly fatal.

Distribution of calcium binding proteins in sensory organs of the ear, nose and throat

Distributions of spot-35 protein (S-35), calbindin (CaB), and parvalbumin (PaV), three types of calcium-binding protein, were examined immunohistochemically in sensory organs of the ear, nose and throat in guinea pigs and rats. Immunoreactivity of S-35 and CaB was found in the outer hair cells and in vestibular sensory cells situated at the top of the ampulla, and in some cells in the macula. Microvillar cells in the olfactory epithelium, periglomerular cells, and small numbers of cells in the mitral cell layer in the olfactory bulb reacted to anti-S-35 and anti-CaB antisera. In taste buds, most gustatory receptor cells reacted to anti-CaB, although a few reacted to anti-S-35 antiserum. Neuron-like cells in the upper respiratory tract reacted similarly to these antisera. No PaV-immunoreactivity was found in any region. These results indicate that S-35 and CaB play important roles in the special kinds of mechanoreceptor and chemoreceptor cells found in the otolaryngeal area.

Moderately differentiated neuroendocrine carcinoma of the larynx. A clinicopathologic study of 54 cases

Fifty-four cases of primary laryngeal moderately differentiated neuroendocrine carcinoma from the Armed Forces Institute of Pathology Otolaryngic Tumor Registry (AFIP-OTR) are reported. The tumors most often present in men in their sixth and seventh decades of life and are heralded by an array of symptoms, the most frequent being hoarseness. The primary site was most often the supraglottic larynx. The investigation has included light-microscopic, histochemical, immunocytochemical, and electron microscopic analyses which support expression of both neuroendocrine and epithelial differentiation. Conservative surgery alone can be utilized if early identification of the tumor and complete surgical removal are assured. The follow-up of the patients reveals 62% as remaining tumor-free after surgical extirpation over periods ranging from 1 month to 16 years (median: 3 years, 9 months). Factors adversely affecting prognosis include metastatic disease at initial presentation, incomplete surgical removal, and vascular or lymphatic invasion. There was no correlation between tumor size, morphologic pattern, mitoses or necrosis, and survival. Sixty-eight percent of the patients gave a history of long-term cigarette smoking. The classification and pathogenesis of these neoplasms remains the focus of much speculation. They are suggested as arising from the cells of the dispersed neuroendocrine system (DNES). However, a more uniform and descriptive nomenclature is necessary. This study resolves this and other issues along with a presentation of clinicopathologic data of the tumor entity.