Immunohistochemical and fine structural characterization of primary carcinoid tumors of the larynx

Abstract

Carcinoid tumors belong to the group of neuroendocrine tumors of epithelial origin, i.e., neuroendocrine carcinomas. These neoplasms usually occur in the gastrointestinal tract or bronchial system but are very rare neoplasms in the larynx. Since carcinoid tumors in this latter site may appear to be undifferentiated by light microscopy, they may possibly be misinterpreted and their neuroendocrine characteristics may remain unrecognized. Using immunohistochemical methods, three carcinoid tumors were studied and showed positive immunostaining for markers of epithelial origin (cytokeratins, epithelial membrane antigen, carcino-embryonic antigen) and, in particular, for markers of neuroendocrine differentiation (chromogranin, synaptophysin, neuron-specific enolase). All tumors expressed calcitonin-, serotonin- and adrenocorticotropic-hormone-like immunoreactivity. In contrast, three poorly differentiated squamous cell carcinomas showed positive immunostaining for epithelial markers but did not show any immunoreactivity with markers of endocrine characteristics. Fine structurally, carcinoid tumor cells contained neurosecretory-type granules scattered throughout the cytoplasm. The present study demonstrated that (1) carcinoid tumors of the larynx possess distinct immunohistochemical characteristics that allow a clear classification, (2) it is advisable to use a battery of primary antibodies rather than rely on specificity and sensitivity of a single marker to establish diagnosis and (3) the fine structural demonstration of neurosecretory-type granules serves as a reliable adjunct to diagnosis.

Clinical recommendations on the treatment of neuroendocrine carcinoma of the larynx: A meta-analysis of 436 reported cases

“…The literature on NCL is fragmented over numerous case reports and series of small sample size, often with contradicting results, making it difficult to decide on an appropriate treatment strategy. Consequently, physicians facing these tumors often resort to treatment paradigms developed for better known neoplasms (eg, squamous cell carcinoma).…”

Unusual features of metastatic atypical carcinoid of the larynx

“…The differential diagnosis of neuroendocrine neoplasms in the larynx comprises poorly differentiated squamous cell carcinoma, extramedullary plasmacytoma, Ki-1 lymphoma, thyroid medullary carcinoma, melanoma, alveolar soft part sarcoma, hemangiopericytoma, and salivary gland acinic cell carcinoma [4,13]. We also suggest that granular cell myoblastoma and signet-ring cell lymphoma could be considered.…”

“…Neuroendocrine carcinomas of the larynx are now classified into three distinct subtypes: typical carcinoid (welldifferentiated neuroendocrine carcinoma), moderately differentiated atypical carcinoid, and undifferentiated small cell carcinoma [2,5,8,14]. The typical carcinoid has a benign clinical behavior and does not cause "carcinoid syndrome" [2,4]. Atypical carcinoids are locally invasive tumors, although metastases to distant sites and organs have been described [3,7].…”

“…Neuroendocrine tumors of the larynx are rare neoplasms, representing 0.6% of all laryngeal neoplasms [4,8]. Recently, they have been separated according to histogenesis, histopathological findings and biological behavior into two major groups: carcinoma and paraganglioma [14].…”

Primary Neuroendocrine Carcinoma of the Uterine Cervix Treated With Complete Surgical Resection and Adjuvant Combination Chemotherapy

“…Pelvic magnetic resonance imaging [13] demonstrated a cervical mass of 3 cm in diameter with right parametrial space Large Cell Neuroendocrine Carcinoma of Cervix J Clin Gynecol Obstet. 2017;6(1):23-27 invasion ( Fig.…”