Metastasizing neuroendocrine carcinoma of the larynx with calcitonin and somatostatin secretion and CEA production, resembling medullary thyroid carcinoma

Primary Neuroendocrine Carcinoma of the Ileum With Markedly Elevated Carcinoembryonic Antigen (CEA) Levels: A Case Report

Neuroendocrine carcinomas (NECs) are rare and highly malignant tumors with a generally poor prognosis. Carcinoembryonic antigen (CEA) is often associated with adenocarcinoma, but its significant elevation in NEC cases is unusual. A 69-year-old man was admitted to our hospital in January 2016 due to syncope induced by anemia. The patient had a hemoglobin level of 8.0 g/dL and an ileocecal mass causing small bowel obstruction on computed tomography. His CEA level was markedly elevated at 3625.4 ng/mL. A colonoscopy revealed a neoplastic lesion in the terminal ileum, leading to an emergency ileocecal resection. Pathology confirmed a NEC, positive for synaptophysin and CEA, with a Ki-67 index of 30%. The patient was diagnosed with stage IIIb NEC (pT3N2M0). A postoperative increase in CEA to 4124.6 ng/mL and metastases in the right lung and multiple lymph nodes were detected. Initial chemotherapy with irinotecan, cisplatin (IP), and octreotide acetate proved ineffective. Subsequent octreoscans showed disease progression. Switching to everolimus as second-line therapy temporarily decreased CEA levels and tumor size, but the disease progressed with cervical lymph node involvement. The patient underwent palliative radiotherapy but succumbed to disease progression in May 2018, with a final CEA level of 36,643 ng/mL. Necropsy of the cervical lymph nodes was consistent with the original surgical findings. This case highlights the aggressive nature and challenging management of NEC with significantly elevated CEA levels.

Laryngeal Neuroendocrine Tumor With Elevated Serum Calcitonin: A Diagnostic and Therapeutic Challenge. Case Report and Review of Literature

Introduction: Laryngeal neuroendocrine neoplasms (NENs) are a rare group of NENs of the neck, which commonly show immunostaining for calcitonin. Laryngeal NENs with calcitonin hypersecretion and lymph node metastases represent a diagnostic and therapeutic challenge, which should be included in the differential diagnosis of medullary thyroid carcinoma (MTC). We report a complex case of laryngeal NEN with calcitonin hypersecretion and a review of the literature. Case Presentation: A 59-year-old man presented with dysphagia, dyspnea, and lateral cervical mass; he was a smoker. At first imaging, a laryngeal lesion with lateral cervical lymphadenopathies was found, and it resulted as a moderately differentiated neuroendocrine tumor (G2), Ki67 = 5%, positive for calcitonin. Increased levels of serum calcitonin (50 pg/ml) were found. The patient started somatostatin analogs for lesions positivity to somatostatin receptor-based imaging. After 5 months, the disease progressed at 18F-fluorodeoxyglucose (¹⁸F-FDG) PET-CT, and also new painful cutaneous lesions occurred. Considering high serum levels of calcitonin, differential diagnosis with MTC was required. Patient performed a thyroid color Doppler ultrasound, nodule fine needle aspiration, calcitonin dosage in fine needle washout fluid, and a calcium gluconate stimulation test. After multidisciplinary evaluation, we decided to perform a total thyroidectomy associated with lateral cervical lymphadenectomy and resection of skin metastases. No MTC was found. Two of the five resected lymph nodes, left upper parathyroid, and skin lesions were metastases of NEN G2, positive for calcitonin. After 2 months, new painful skin lesions occurred, and a target therapy with everolimus 10 mg/day was started. After 6 months of therapy, partial metabolic response with a reduction of 53.7% of radiotracer uptake at primary tumor was detected together with an improvement of patient's quality of life. Conclusions: The present case is the seventh described in the literature of laryngeal NEN associated with elevated serum calcitonin levels and the first case with parathyroid metastasis, suggesting the importance of a correct differential diagnosis between MTC and calcitonin-secreting laryngeal NEN, using an integrated approach of biochemistry and advanced imaging. This is also the first time that somatostatin analogs and then everolimus were used in this setting, resulting in clinical and partial metabolic response.

A Calcitonin-Producing Neuroendocrine Tumor of the Larynx: A Case Report

A moderately differentiated neuroendocrine carcinoma of the larynx is described. Although the patient had normal serum calcitonin level 36 months before, its level was elevated at the time the neck node was removed. This study supports the hypothesis that a diagnosis of calcitonin-producing neuroendocrine tumor of the larynx with increased plasma calcitonin is possible and should be considered to avoid unnecessary thyroidectomy.

Metastatic medullary thyroid carcinoma or calcitonin-secreting carcinoid tumor of lung? A diagnostic dilemma in a patient with lung mass and thyroid nodule

Calcitonin-secreting neuroendocrine tumors are rare and have been reported in literature as case reports or case series in various organs including lung, pancreas, larynx, bladder, and ovary. These tumors have similar cytologic features and immunohistochemical profile to medullary thyroid carcinoma and thus it is difficult to distinguish them, especially when calcitonin-secreting neuroendocrine tumors are intermediate or higher grade and there is a mass lesion in the thyroid gland. Here, we report a rare case of calcitonin secreting atypical carcinoid tumor of the lung in a patient with thyroid nodule. However, after extensive ancillary studies on the thyroid gland, no tumor was detected and subsequent resection specimen revealed a pulmonary atypical carcinoid tumor with metastasis to level 11 lymph node. Being aware of this entity has significant clinical, diagnostic, and therapeutic implications and can prevent unnecessary thyroidectomies with subsequent possible morbidities.

Metastatic neuroendocrine tumor of the esophagus with features of medullary thyroid carcinoma

A 41-year-old female presented with a pedunculated mass in the upper esophagus and bilateral lymphadenopathy. Biopsies suggested a neuroendocrine tumor, possibly carcinoid, and ensuing imaging revealed cervical lymph node metastases. The esophageal mass was removed endoscopically and discovered by pathologists to closely resemble medullary thyroid carcinoma (MTC) on immunohistochemistry staining. Following surgery, further work up demonstrated very high serum calcitonin levels, suggestive of medullary thyroid carcinoma, however the thyroid gland was normal on ultrasound. The patient underwent a neck dissection to remove the lymph node metastases and subsequently her calcitonin levels dropped to 0 ng/mL, indicating remission. It appears that the primary tumor was not in the thyroid, but in the cervical esophagus. The thyroid has appeared normal on multiple ultrasounds without any detectable nodules or masses. This is quite a unique case because this patient presented with a tumor resembling medullary carcinoma of the thyroid that presented as a pedunculated mass in the cervical esophagus. The actual final diagnosis of this mass in the cervical esophagus was neuroendocrine tumor (NET), consistent with a carcinoid tumor, not ectopic MTC. This case report highlights that calcitonin-secreting tumors outside the thyroid should not lead to erroneous recommendations for thyroidectomy.

Can Medullary Thyroid Carcinoma Arise in Thyroglossal Duct Cysts? A Search for Parafollicular C-cells in 41 Resected Cases

Thyroglossal duct cysts (TGDCs) are present in ~7% of adults and develop from the midline migratory tract between the foramen cecum and anatomic location of the thyroid. Thyroid tissue can be identified in 2/3 of TGDCs, and up to 1% develop associated malignancy, 90% of which are papillary thyroid carcinoma. Cases of follicular and anaplastic carcinoma have been documented, but there are no reports of medullary thyroid carcinoma arising in a TGDC. This is presumably due to the distinct embryologic origin of parafollicular C-cells, from which medullary carcinoma arises. The goal of this study is to determine whether parafollicular C-cells are present in TGDCs. H&E sections from 41 TGDC cases were examined for thyroid tissue, thyroglossal duct remnants, ultimobranchial remnants, and parafollicular C-cells. Immunohistochemistry was performed for TTF-1 and calcitonin. Eighty three percent (34/41) of cases contained thyroid tissue on H&E and by TTF-1. No cases (0/41) had ultimobranchial remnants or parafollicular C-cells on H&E or with calcitonin. One case of papillary carcinoma in a TGDC was identified. These cases illustrate that although TGDCs often contain thyroid tissue, parafollicular C-cells are absent. Therefore, unlike other thyroid neoplasms, there is no evidence to support the possibility of medullary carcinoma arising in a TGDC.

[Thyroid C cells and their pathology: Part 2: Medullary thyroid carcinoma]

All tumours with C cell differentiation are designated as medullary carcinomas (MTC). MTC occur sporadically (75-80%) or hereditary (20-25%), the latter being part of the multiple endocrine neoplasia type 2. Familial MTC, which is commonly preceded by "neoplastic" C cell hyperplasia, is caused by autosomal-dominant inherited germ line mutation of the RET-protooncogene; dependent on the codon affected by the mutation, patients show substantially different clinical courses. Due to its morphological heterogeneity, the immunohistochemical demonstration of calcitonin is mandatory for the diagnosis of MTC. For early diagnosis of MTC calcitonin screening has been introduced in Germany and Austria approx. 10 years ago in patients with thyroid nodules; however, an increased calcitonin serum level may also be caused by "non-MEN2-associated" C cell, which is not regarded as a precursor of sporadic MTC. Very rarely tumours may show a mixed C cell-follicular cell differentiation.

[Thyroid C cells and their pathology: Part 1: normal C cells, - C cell hyperplasia, - precursor of familial medullary thyroid carcinoma]

The C cells (parafollicular) of the human thyroid gland are predominantly located within the thyroid follicles, are of neuroendocrine origin and produce and secrete the peptide hormone calcitonin. Calcitonin is clinically utilized as a screening marker to detect occult medullary thyroid carcinoma (MTC) as well as in the follow-up of patients with MTC. An increase in the number of C cells is designated as C cell hyperplasia (CCH). Neoplastic CCH is caused by an autosomal dominant inherited mutation of the RET protooncogene, which develops into invasive familial MTC in the setting of multiple endocrine neoplasia (MEN) type 2 depending on the location of the mutation in the RET gene with a high variation in latency. According to the current state of knowledge CCH without a germline mutation in the RET protooncogene, designated as non-MEN2-associated CCH, seems to be unrelated to the development of sporadic MTC.

Calcitonin-Secreting Neuroendocrine Carcinoma of Larynx with Metastasis to Thyroid

Primary neuroendocrine tumors of the larynx are rare, with moderately differentiated neuroendocrine carcinoma (MDNC) being the most frequent histologic type. We report a MDNC in a 57-year-old gentleman with an enlarging right-sided neck mass. Flexible fiberoptic exam revealed a right arytenoid lesion. Histology from excisional biopsy was concerning for medullary thyroid carcinoma (MTC) versus NET of the larynx. Immunohistochemistry was diffusely positive for calcitonin and CEA and focally positive for TTF-1. Serum calcitonin was elevated. Thyroid ultrasound was unremarkable. The patient underwent laryngectomy, thyroidectomy, and neck dissection. Pathology showed neuroendocrine carcinoma of right arytenoid with positive cervical lymph nodes. A 4 mm deposit of NET was present in right thyroid with adjacent intravascular tumor consistent with thyroidal metastasis from a primary laryngeal NET (MDNC). MDNC and MTC can be microscopically indistinguishable. Both tumors can stain positively for calcitonin and CEA. TTF-1 staining has been useful to help distinguish these tumors as it is strongly and diffusely positive in MTC, but usually negative (or only focally positive) in MDNC. We report the fourth case of primary neuroendocrine carcinoma of the larynx associated with elevated serum calcitonin level and the first such case associated with metastasis to the thyroid.

Histopathology of C Cells and Medullary Thyroid Carcinoma

The human thyroid gland contains less than 0.01-0.1% calcitonin producing and secreting C cells, which in men are almost exclusively situated in an intrafollicular location; the vast majority of C cells are embryologically derived of remnants of the ultimobranchial body and ultimately of the neural crest, a small subset, however, is presumed to originate from endodermal stem cells. Thyroid tumours with C cell differentiation have been named medullary thyroid carcinoma (MTC); calcitonin is also produced and secreted by MTC which makes this peptide hormone a very useful serum marker both for early detection and clinical follow-up of patients with MTC. About 70-80% of MTC are sporadic tumours, whereas 20-30% are familial MTC which are autosomal-dominant inherited and caused by germline mutations of the RET proto-oncogene located on chromosome 10. This article summarizes the histological, immunhistochemical and molecular genetic features of C cells, C-cell hyperplasia (CCH) and MTC, emphasizing the role of diagnostic pathology.

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

BACKGROUND

Current recommendations on the treatment of neuroendocrine carcinoma of the larynx (NCL) are based on anecdotal evidence. With this meta-analysis, our purpose was to provide clinicians with more substantiated guidelines in order to improve the treatment outcome of the patients affected with NCL.

METHODS

A structured literature search for all research concerning NCL was performed against the MEDLINE and EMBASE databases. Available data was normalized, pooled, and statistically analyzed.

RESULTS

Four hundred thirty-six cases of NCL were extracted from 182 studies, of which 23 were typical carcinoid, 163 were atypical carcinoid, 183 were small-cell neuroendocrine carcinoma, 29 were large-cell neuroendocrine carcinoma, and 38 were unspecified carcinoid tumors. The 5-year disease-specific survival (DSS) was 100% for typical carcinoid, 53% for atypical carcinoid, 19% for small-cell neuroendocrine carcinoma, and 15% for large-cell neuroendocrine carcinoma (p < .001). Patients with an atypical carcinoid treated with surgery had better DSS than those treated with radiotherapy (60% vs 54%; p = .035). Postoperative radiotherapy did not result in better DSS in atypical carcinoid. Patients with an atypical carcinoid, not undergoing surgical treatment of the neck, developed isolated regional recurrence in 30% of cases (p = .001). Radiochemotherapy yielded the best DSS for small-cell neuroendocrine carcinoma compared to other modalities (31% vs 13%; p = .001).

CONCLUSION

Typical carcinoid can be treated by local excision alone. Atypical carcinoids do not seem to respond well to radiotherapy and are best managed through radical surgical excision in combination with elective neck dissection. Patients with small-cell neuroendocrine carcinoma or large-cell neuroendocrine carcinoma seem to benefit most from chemoradiotherapy.

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.

A carcinoid tumor mimicking an isolated intracranial meningioma

✓ This 79-year-old woman presented with progressively worsening dementia, abulia, flat affect, urinary incontinence, and profuse watery diarrhea. Results of computerized tomography and magnetic resonance studies indicated an extraaxial, dural-based mass compressing the right frontal lobe and consistent with a convexity meningioma. A right frontal craniotomy was performed and the dural-based mass was resected. Histopathological features on immunostaining of the lesion were consistent with a carcinoid tumor (low-grade neuroendocrine carcinoma). Further evaluation revealed no primary carcinoid tumor in the foregut from which they typically originate. The authors concluded that this intracranial carcinoid tumor was the primary lesion despite its unusual location and that it should be included in the differential diagnosis of dural-based, extraaxial brain lesions.

A Study of Moderately Differentiated Neuroendocrine Carcinomas of the Larynx and an Examination of Non-Neoplastic Larynx Tissue for Neuroendocrine Cells

OBJECTIVES/HYPOTHESIS

To determine the most appropriate terminology for neuroendocrine carcinomas (NEC) of the larynx, successive clinicopathologic studies are encouraged. The typical location and immunophenotype of laryngeal NEC raise a question of whether any precursor cells exist.

STUDY DESIGN

Six patients with laryngeal NEC were analyzed. Another 20 laryngectomy specimens were examined for the presence of non-neoplastic neuroendocrine cells.

METHODS

Tumor morphology and patient outcome were determined, and tumor tissue underwent immunohistochemical examination to identify cytokeratin, neuroendocrine markers (chromogranin, synaptophysin, CD56, calcitonin), S-100 protein, and p53 protein. A neuroendocrine marker study was also performed on non-neoplastic regions of another 20 laryngectomy specimens to identify any neuroendocrine cells.

RESULTS

Laryngeal NEC, all submucosal, exhibited various morphology with or without histologic evidences of neuroendocrine differentiation. The tumors showed frequent (67%) calcitonin expression, calcitonin secretion in one case, and common (50%) p53 over-expression. Three patients died within 3 years. In the non-neoplastic larynx specimens, Kulchitsky cell-like bipolar neuroendocrine cells were identified in the basal and middle layer of the respiratory epithelium of the ventricle and subglottis but none in the submucosal layer of the supraglottic region. The neuroendocrine cells did not express calcitonin.

CONCLUSIONS

Moderately differentiated or large-cell NEC is a more favored term than atypical carcinoid until more refined classifications for upper respiratory tract NEC are agreed on. Despite the confirmed presence of neuroendocrine cells in the respiratory epithelium of the larynx, the origin of laryngeal NEC remains unknown. p53 mutation might be one of the major molecular steps in the pathogenesis of laryngeal NEC.

Thyroid transcription factor-1, but not p53, is helpful in distinguishing moderately differentiated neuroendocrine carcinoma of the larynx from medullary carcinoma of the thyroid

Moderately differentiated neuroendocrine carcinoma/atypical carcinoid tumor is the most common nonsquamous malignancy in the larynx; however, due to morphologic overlap and calcitonin immunoreactivity, it can be difficult to distinguish from thyroid medullary carcinoma. Currently, low serum calcitonin is the most reliable means for distinguishing primary laryngeal moderately differentiated neuroendocrine carcinoma from metastatic medullary carcinoma. Thyroid transcription factor-1 (TTF-1) is positive in at least 80% of medullary carcinomas, but has not been evaluated in laryngeal moderately differentiated neuroendocrine carcinomas. Additionally, it has been suggested that p53 is positive in laryngeal moderately differentiated neuroendocrine carcinomas and negative in other neuroendocrine tumors, but this has not been validated. The purpose of this study was to determine if the immunohistochemical markers TTF-1 and p53 could be used to discriminate between laryngeal moderately differentiated neuroendocrine carcinomas and thyroid medullary carcinomas. Eight laryngeal moderately differentiated neuroendocrine carcinomas and 10 thyroid medullary carcinomas were identified from the archival files of the BWH and MGH Pathology Departments. Hematoxylin and eosin slides were reviewed, and immunohistochemistry was performed using antibodies to calcitonin, TTF-1, and p53. Calcitonin immunohistochemistry demonstrated immunoreactivity in 100% of laryngeal moderately differentiated neuroendocrine carcinomas (N=8) and 100% of thyroid medullary carcinomas (N=10). There was weak, focal immunoreactivity with TTF-1 in one of eight (13%) laryngeal moderately differentiated neuroendocrine carcinomas, whereas nine of ten (90%) medullary carcinomas were positive for TTF-1, with strong diffuse staining in seven of these cases (78%). p53 was positive in three of six (50%) laryngeal moderately differentiated neuroendocrine carcinomas, and three of ten (30%) medullary carcinomas. Our data demonstrate that immunoreactivity for TTF-1, but not calcitonin or p53, may be helpful in distinguishing laryngeal moderately differentiated neuroendocrine carcinoma and thyroid medullary carcinoma. In particular, diffuse and/or strong TTF-1 immunoreactivity favors a diagnosis of primary thyroid medullary carcinoma over laryngeal moderately differentiated neuroendocrine carcinoma.

A review of neuroendocrine neoplasms of the larynx: update on diagnosis and treatment

Neuroendocrine neoplasms of the larynx have been divided into those of epithelial or neural origin. The latter consist of paragangliomas while the epithelial origin group can be divided into the typical and atypical carcinoids and small cell neuroendocrine carcinomata, the latter consisting of the oat cell type, the intermediate cell type and the combined cell type. There are now over 500 cases of neuroendocrine neoplasms of the larynx in the literature. The diagnosis is primarily based on light microscopy, and, in some instances, it may be supported by special histochemical studies. It should be confirmed by immunocytochemical and/or ultrastructural investigation. The different biological behaviour of neuroendocrine neoplasms of the larynx makes a specific diagnosis of paramount importance, since treatment depends on diagnostic accuracy. Typical carcinoid is an extremely rare lesion. It is treated preferably by conservative surgery; elective neck dissection is not necessary because of the lack of lymph node metastases at diagnosis. Chemotherapy and/or radiotherapy have not been effective in the limited number of patients treated thus far. Prognosis is excellent with cure following surgery. Atypical carcinoid is the most frequent non-squamous carcinoma of the larynx. The mainstay of treatment is surgery. Elective neck dissection should be performed because of the high likelihood of cervical lymph node metastases. Primary radiation therapy with adjuvant chemotherapy is not indicated. The survival rate is 48 per cent at five years and 30 per cent at 10 years. Although the larynx is one of its most common extrapulmonary sites, small cell neuroendocrine carcinoma is still a rare tumour. Surgical results for this tumour have been disappointing and is reserved for cases of local relapse with no evidence of metastasis. Chemotherapy and radiotherapy currently appear to offer the least disabling and most effective forms of therapy. The two- and five-year survival rates are 16 per cent and five per cent, respectively. Paraneoplastic syndromes have occasionally been reported in association with carcinoid tumours (typical and atypical) and small cell neuroendocrine carcinoma. There have been also rare reports of an elevated neuropeptide serum level. Paraganglioma is the only laryngeal neuroendocrine neoplasm with a female preponderance (3:1). Confusion with atypical carcinoid has led to incorrect diagnosis and inappropriate classification schemes, erroneously suggesting that laryngeal paraganglioma has the potential for aggressive behaviour. Conservative surgery represents the treatment of choice; elective neck dissection is not necessary, and the prognosis is excellent.

Atypical carcinoid of larynx: presentation with scalp metastases

A case of atypical carcinoid tumour of the larynx in a 72-year-old woman is presented. The neoplasm was located in the supraglottic region and was first manifest by metastases to the scalp. The presence of amyloid-like material and calcitonin-positive cells were features that resembled medullary carcinoma of the thyroid. Clinically, it pursued an aggressive course that led to death 58 months after diagnosis. The literature is reviewed, particularly that regarding the differential diagnosis.

Neuroendocrine Tumors of the Head and Neck: A Selected Review with Emphasis on Terminology

Virtually every variant of neuroendocrine neoplasia can occur, at least rarely, in the head and neck region. This review focuses on the terminology surrounding neuroendocrine carcinomas of the larynx and their distinction from morphologically similar but biologically distinctive neoplasms. It is suggested that rare typical laryngeal carcinoids be labeled as such. There is little evidence that these lesions are part of a morphologic continuum. In contrast, more common "carcinoid-like" carcinomas, previously referred to as "atypical carcinoids" are more appropriately labeled as "moderately differentiated neuroendocrine carcinomas." These neoplasms should, in turn, be distinguished from "small cell neuroendocrine carcinomas," although these latter two neoplasms do represent a morphologic and behavioral spectrum. Light microscopic and immunohistochemical features distinguishing neuroendocrine carcinomas of the larynx from paraganglioma, metastatic medullary carcinoma, malignant melanoma, and basaloid squamous cell carcinoma are presented. The second portion of this review outlines the clinicopathologic features of two head and neck neoplasms exhibiting varying degrees of neuroendocrine differentiation. Olfactory neuroblastomas have well-developed neuroendocrine differentiation, almost invariably arise from the olfactory mucosa, typically exhibit low-grade cytologic features, and may have protracted clinical course with an approximately 50% overall 5-yr survival. In contrast, sinonasal undifferentiated carcinoma is a microscopically high-grade neoplasm with minimal, abortive neuroendocrine features, a highly aggressive clinical course, and virtually 100% mortality. They can arise throughout the sinonasal region.

Immunohistochemical markers in the diagnosis of neuroendocrine neoplasms of the head and neck

Immunohistochemistry is important in the diagnosis of neuroendocrine neoplasms of the head and neck, particularly in the differential diagnosis of the various neuroendocrine neoplasms, although the results of staining should never be interpreted alone, but together with conventional histopathologic findings. It is emphasized that there are currently no markers capable of distinguishing between benign and malignant tumors. A correct diagnosis is of paramount importance, since treatment depends on the diagnostic accuracy and prognosis is naturally related substantially to the phenotype.

Laryngeal paraganglioma versus atypical carcinoid tumor

Paraganglioma and atypical carcinoid tumor of the larynx are two neuroendocrine neoplasms that have often been confused in the past, and even in the present, in the literature. The clinicopathological profile of the two lesions is presented and the differential diagnosis is discussed. A correct diagnosis is of paramount importance, since treatment and prognosis depend on diagnostic accuracy and differ for the two lesions. Paraganglioma of the larynx is usually benign, whereas atypical carcinoid tumor is malignant and has an aggressive clinical course.

Medullary (thyroid) carcinoma-like carcinoids of the larynx

The histopathological spectrum of neuroendocrine neoplasms of the larynx includes a subset that may be indistinguishable from a medullary carcinoma of the thyroid gland. For a patient who presents with a medullary carcinoma-like metastasis in a cervical lymph node and in whom there is no clinically demonstrable thyroid lesion, a laryngeal atypical carcinoid must be excluded. The literature's third example of a primary medullary carcinoma-like atypical carcinoid of the larynx is presented.