Discussion
We describe a rare case of laryngeal NEN in subglottic. While many laryngeal neuroendocrine carcinomas found in the supraglottic, in about 60 to 96 percent of casese.4
Although primary neuroendocrine carcinomas are rare, they are the most common non-squamous neoplasm of the larynx. Based on 2017 WHO Classification of Head and Neck Tumors, neuroendocrine tumors of the larynx are classified as well-differentiated neuroendocrine carcinoma: typical carcinoid; moderately differentiated neuroendocrine carcinoma: atypical carcinoid; poorly differentiated neuroendocrine carcinoma: small and large cell neuroendocrine carcinoma, and paragangliomas which have a neural origin. Moreover, based on Neuroendocrine carcinoma (NEC) classification as suggested by the International Agency for Research on Cancer (IARC) and World Health Organization (WHO), in poorly differentiated epithelial neoplasms, Microscopic histopathologic analysis showing tumor necrosis, and mitotic rate of > 10/2 mm2.5
Atypical carcinoid is the most common neuroendocrine carcinomas of the larynx that represents 0.2% - 0.6% of laryngeal malignancies.3, 5Also, atypical carcinoid has more aggressive character that metastasis to cervical lymph nodes, bone, skin, liver, and lung are frequent in their disease nature .6,7Laryngeal NENs typically affect middle-aged patients with a history of heavy smoking with a male preponderance.8The common clinical manifestations are Hoarseness, dysphagia, and sore throat. In rare cases paraneoplastic syndrome happens. Moreover, cervical lymph node metastases and cutaneous metastases may detect in some cases.9
With this in mind, treatment and prognosis of the various NEC groups differ; precise identification of tumor group is critical. Although, surgery is usually the treatment for all tumor type, chemotherapy may be utilized for moderately to poor differentiated NECs. Laryngeal well-differentiated NEC is treated with wide local excision, generally a partial laryngectomy, without neck dissection. While, in moderately differentiated NECs partial or total laryngectomy with elective or therapeutic neck dissection is necessary. However, adjuvant chemo radiotherapy may be beneficial in some case. Eventually, chemo radiotherapy is recommended for poorly differentiated NECs because surgery is ineffective in these group.10Furthermore, tumor prognosis differs among various tumors types. A 5-year disease-specific survival rate is about100%, 53%, 19%, and 15%, in Well-differentiated NEC, Moderately differentiated NEC, small cell NEC, and large cell NEC respectively.4