LETTER TO THE EDITOR
NEUROENDOCRINE TUMORS OF THE LARYNX TO THE EDITOR:
I read with interest the recent article by Moisa.’ Although the article is both detailed and informative, I believe there are several major flaws in the manuscript which do a disservice to the subject of laryngeal neuroendocrine tumors, as well as to your readership. The first of the aforementioned problems is the fact that Dr. Moisa essentially equates carcinoid tumors with laryngeal large cell neuroendocrine cancers (page 499, first paragraph). The latter were described by Woodruff et a1.2 who found that laryngeal large cell tumors were aggressive neoplasms capable of metastatic disease and proved to be highly fatal. Those authors subclassified the laryngeal neuroendocrine carcinomas into large cell and small cell groups both of which are high-grade cancers. Laryngeal carcinoids are indolent neoplasms cured by surgical excision, and there are no associated reported incidences of mortalities related to laryngeal carcinoid turn or^.^-^ The second major problem with the article relates to the absence of any references beyond 1987. Considering that the article was accepted for publication on February 25, 1991, and that it does not include any references beyond 1987, I question the contentions made in the article and the validity of the statement “A comprehensive review of the international literature revealed . . .” (page 505, paragraph three).’ This not only relates to the classification proposed by Moisa making it highly suspect but precludes publications extensively dealing with the subject of classification, nomenclature, histogenesis, pathology, differential diagnosis, treatment, and biology in relation to the entire spectrum of laryngeal neuroendocrine neoplasm~.~-~ The third major problem with the article, one that directly relates to the absence of inclusion of a recent literature search, is the subject of laryngeal paragangliomas, particularly the so-called malignant paragangliomas or metastasizing laryngeal paragangliomas. This issue has been detailed by me and other author^^-^*^ who feel that based on numerous clinical
332
Letter to the Editor
and pathologic parameters, as well as the exceedingly rare occurrence of laryngeal paragangliomas, that many if not all of these so-called malignant paragangliomas or metastasizing laryngeal paragangliomas are, in fact, neuroendocrine carcinomas that have been erroneously diagnosed as p a r a g a n g l i ~ m a s . ~ - ~ This is further highlighted by the fact that the vast majority of malignant paragangliomas (as diagnosed by the presence of metastases) primarily arise in the retroperitoneum and in relation to the vagal body.6 In Dr. Moisa’s description of laryngeal paragangliomas, he notes the cell nest (Zellballen) pattern surrounded by fibrovascular stroma as characteristic of paragangliomas. This is true. However, this histology is not pathognomonic for paragangliomas. The identical patterns, as well as cytomorphologic appearances are seen in neuroendocrine tumors of the larynx.324 Dr. Moisa describes the immunocytochemical findings identified in the three neoplastic groups he proposes; however, the antigenic profile cited does not differentiate any of these neoplasms. In fact, there is much overlap in the immunocytochemical reactivity of neuroendocrine tumors in general. Paragangliomas have characteristic staining of the peripherally located sustentacular cells by S-100 protein, a fact not detailed by Dr. Moisa. Along these lines, the author cites neurospecific enolase [the appropriate nomenclature for this antibody is neuron-specific enolase (NSE)] as being the most representative marker for neuroendocrine tumors. This is erroneous and further highlights the absence of an acceptable literature search. Among pathologists, NSE is often sarcastically referred to as “nonspecific” enolase emphasizing the fact that this antibody cross reacts with cells of divergent histogenesis not only with neuroendocrine lesions. The most useful immunocytochemical marker in neuroendocrine lesions is chromogranin described in the early 1980~.~,’ Although Dr. Moisa does mention the controversy regarding the diagnosis of laryngeal paragangliomas in passing (page 503, third paragraph), to report the existence of 68 laryngeal paragangliomas- stating that laryngeal paragangliomas have a considerable
HEAD & NECK
July/August 1992
malignant potential with an indeterminate biologyand not to have detailed the argument surrounding this diagnosis as well as the evidence supporting the contention that the metastasizing and/or lethal laryngeal paragangliomas are neuroendocrine carcinomas, represents a misunderstanding of the subject as well as a less-than-exhaustive search into the subject matter. Finally, while paragangliomas are unquestionably neuroendocrine lesions, they should not be classified or categorized along with the laryngeal neuroendocrine carcinomas because of the differences in biologic behavior. I believe, as indicated above, that the article by Dr. Moisa contains numerous serious problems not the least important of which is the absence of an up-todate literature search. This flaw not only rests on the author’s shoulders, but the editorial staff of Head & Neck bears equally if not a greater share of the onus for the problems inherent in the article. Bruce M. Wenig, MD Department of Otolaryngic-Endocrine Pathology Armed Forces Institute of Pathology Washington DC 1. Moisa 11. Neuroendocrine tumors of the larynx. Head Neck 1991;13:498- 508. 2. Woodruff JM, Huvos AG, Erlandson FL4, Shah JP, Gerold
FP. Neuroendocrine carcinomas of the larynx: a study of two types, one of which mimics thyroid medullary carcinoma. Am J Surg Puthol 1985;9:771-790. 3. Wenig BM, Hyams VJ, Heffner DK. Moderately differentiated neuroendocrine carcinomas of the larynx: a clinicopathologic study of 54 cases. Cancer 1988;62:2658-2676. 4. Wenig BM, Gnepp DR. The spectrum of neuroendocrine carcinomas of the larynx. Sernin Diagn Pathol 1989;6:329-350. 5. Ferlito A, Friedmann I, Goldman NC. Primary carcinoid tumor of the larynx. ORL 1990;50:129-149. 6. Batsakis JG, ed. Paragangliomas of the head and neck. In:
Tumors of the head and neck: clinical and pathological considerations, 2nd ed. Baltimore: Williams & Wilkins Co., 1979:369-380. 7. Lloyd RV, Wilson BS. Specific endocrine tissue marker defined by a monoclonal antibody. Science 1983;222:628630. 8 . Wilson BS, Lloyd RV. Detection of chromogranin in neuroendocrine cells with a monoclonal antibody. Am J Pathol 1984;115:458-468.
REPLY:
I would like to thank Dr. Goepfert and the editorial staff of Head & Neck for allowing me to reply to Dr. Wenig’s remarks. Although I appreciate Dr. Wenig’s efforts to update us on the subject of laryngeal neuroendocrine neoplasms, most of his comments are inappropriate and inaccurate. My article’ was intended to organize an extensive, fragmented body of knowledge regarding laryngeal neoplasms demonstrating neuroendocrine differentiation. A review of the international literature was per-
Letter to the Editor
formed, along with several updates. The most current works on this topic a t the time my article was completed were published in 1987. Based on this, nomenclature, classification, and management suggestions were made. In contradistinction to previous reviews, paragangliomas of the larynx (PGL) were classified among the family of neuroendocrine tumors of the larynx (NETL). (This view is currently shared by the World Health Organization and other^.)^,^ Furthermore, unlike many previous reviews, the English as well as the non-English literature were considered. The statement regarding the comprehensive nature of my article regarding NETL appears justified. If my article may be faulted because of a lengthy period between its completion and the time of its submission for publication (July 20, 1990), I assume complete and exclusive responsibility for that. Despite this, the work does not possess the major flaws Dr. Wenig implies. Numerous works regarding laryngeal neuroendocrine neoplasms have appeared since I completed my review. Among the most important of these is a n edition of ORL devoted exclusively to this topic.2 Although there may not have been sufficient detailed information in the literature at the time of my original review‘ on which to base a definite differentiation between carcinoid and atypical carcinoid tumors of the larynx, there seems to be sufficient data upon which to make such a distinction a t the present time.4*5Accordingly, in light of additional material available after my original review was completed, our subsequent article reflected this distinction.6 Although Dr. Wenig has not missed the opportunity t o remind us of his own works, he has apparently not considered what is probably the premier collaborative work on NETL to As a result, most of his remarks are inaccurate. In view of this glaring omission, I find Dr. Wenig’s comments regarding the inadequacy of my review particularly inappropriate. Dr. Wenig states that “Laryngeal carcinoids are indolent neoplasms cured by surgical excision and there are no associated reported incidences of mortalities related to laryngeal carcinoid tumors” (paragraph two). This statement is incorrect. In a recent update of 13 patients with this neoplasm, four patients developed distant metastasis, whereas one patient died of disease. The authors noted that “Typical laryngeal carcinoids are less aggressive than their atypical counterparts but late distant metastasis and death may O C C U ~ . ” ~ Because my review was not intended as an exhaustive histopathologic description of PGL or of the other NETL, such descriptions having been provided by others, this topic was adequately addressed and sufficiently referenced (page 501I.l Contrary to Dr. Wenig’s impression, no attempt was made to suggest a pathognomonic histologic description of PGL. As such, Dr. Wenig’s statements in this matter are inaccurate. The issue regarding the clinical behavior of PGL remains controversial. I addressed this issue appropri-
HEAD & NECK
JulyiAugust 1992
333
ately, citing authors who were of the opinion that PGL are essentially benign and that malignant PGL probably represent misdiagnosed lesions, as well as authors who felt PGL could demonstrate malignant behavior (page 503).’ Some recent workers have noted an incidence of metastatic disease and mortality among PGL similar to my f i g ~ r e s .Although ~ these authors addressed the issue that some malignant PGL reported in the literature may indeed represent misdiagnosed lesions, they nevertheless wisely concluded that “A true estimate of the malignant potential and prognosis of the laryngeal paraganglioma awaits improvements in diagnostic techniques.”’ Others, however, have noted a 3% incidence of malignancy among PGL, concluding that most malignant PGL are in reality atypical carcinoids that may have been misdiagnosed.’ Greater awareness, more precise diagnosis, and closer follow-up of patients with PGL should help to resolve this controversy in the future. At present, however, the most prudent approach may be to consider PGL as mostly benign while possessing a malignant potential, as I have suggested (page 505).l The overlapping ultrastructural and cytochemical characteristics among NETL is obvious from Table 3 (page 5011.l No attempt was made to distinguish between the various NETL based on these features. Therefore, I see no reason for Dr. Wenig’s negative remarks in this matter as he is in agreement with me. The relevance of Table 3,l however, is to demonstrate those features unique to NETL as a group, features that may be used to distinguish NETL as a family of tumors from other laryngeal neoplasms. Dr. Wenig seems to have missed this crucial point entirely. The section entitled “Future Goals” (pages 504- 505)’ addresses the issues of neuroendocrine markers. Contrary to Dr. Wenig’s impression, no suggestion is made to indicate that NSE is a pathognomonic marker for all NETL, since no PGL at the time of my review had been tested for this substance (Table 3).l In fact, I begin the last paragraph of that section by stating that “. . . a characteristic marker for NETL has not been conclusively identified . . .” (page 5051.’ Dr. Wenig’s contention that PGL should not be classified along with the other NETL is contrary to current opinion. The neuroendocrine nature of PGL
334
Letter to the Editor
based on ultrastructural and cytochemical features is obvious.’,’ Furthermore, Dr. Wenig states that “paragangliomas are unquestionably neuroendocrine lesions” (paragraph three, last sentence). Finally, and probably most importantly, the nomenclature “paraganglioma of the larynx” and the inclusion of this neoplasm in the classification of neuroendocrine neoplasms of the larynx (as I proposed)’ have been recently suggested by the World Health organization To’ ’ exclude this tumor and numerous a ~ t h o r i t i e s . ~ ’ ~ from a classification of NETL demonstrates a lessthan-thorough appreciation regarding the entire spectrum of laryngeal neuroendocrine neoplasms. My original suggestions were based on the literature available at the time my review was completed.’ The topic of laryngeal neuroendocrine neoplasms has evolved in recent years, yet many of my proposals have apparently remained appropriate. In fact, many of these recommendations seem to have been independently accepted by others.233 ldel 1. Moisa, M D Department of Otolaryngology
Montefiore Medical Center Bronx, NY
1. Moisa 11. Neuroendocrine tumors of the larynx. Head Neck
1991;13:498-508. 2. ORL, Journal for Oto-Rhino-Laryngology and Its Related Specialties, vol. 53. Basel, Switzerland S. Karger,
1991:185-264.
3. Ferlito A, Rosai J. Terminology and classification of neuroendocrine neoplasms of the larynx. ORL J Otorhino-
laryngol Relat Spec 1991;53:185-187. 4. El-Naggar AK, Batsakis JG. Carcinoid tumor of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:188- 193. 5 . Woodruff JM, Senie RT. Atypical carcinoid tumor of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:194-209. 6. Moisa 11, Silver CE. Treatment of neuroendocrine neoplasms of the larynx. ORL J Otorhinolaryngol Relat Spec 1991;53:259-264. 7. Konowitz PM, Lawson W, Som PM, Urken ML, Breakstone BA, Biller HF. Laryngeal paraganglioma: update on diagnosis and treatment. Laryngoscope 1988;98:40-49. 8. Barnes L. Paraganglioma of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:220-234.
HEAD & NECK
July/August 1992
NEUROENDOCRINE TUMORS OF THE LARYNX TO THE EDITOR:
I read with interest the recent article by Moisa.’ Although the article is both detailed and informative, I believe there are several major flaws in the manuscript which do a disservice to the subject of laryngeal neuroendocrine tumors, as well as to your readership. The first of the aforementioned problems is the fact that Dr. Moisa essentially equates carcinoid tumors with laryngeal large cell neuroendocrine cancers (page 499, first paragraph). The latter were described by Woodruff et a1.2 who found that laryngeal large cell tumors were aggressive neoplasms capable of metastatic disease and proved to be highly fatal. Those authors subclassified the laryngeal neuroendocrine carcinomas into large cell and small cell groups both of which are high-grade cancers. Laryngeal carcinoids are indolent neoplasms cured by surgical excision, and there are no associated reported incidences of mortalities related to laryngeal carcinoid turn or^.^-^ The second major problem with the article relates to the absence of any references beyond 1987. Considering that the article was accepted for publication on February 25, 1991, and that it does not include any references beyond 1987, I question the contentions made in the article and the validity of the statement “A comprehensive review of the international literature revealed . . .” (page 505, paragraph three).’ This not only relates to the classification proposed by Moisa making it highly suspect but precludes publications extensively dealing with the subject of classification, nomenclature, histogenesis, pathology, differential diagnosis, treatment, and biology in relation to the entire spectrum of laryngeal neuroendocrine neoplasm~.~-~ The third major problem with the article, one that directly relates to the absence of inclusion of a recent literature search, is the subject of laryngeal paragangliomas, particularly the so-called malignant paragangliomas or metastasizing laryngeal paragangliomas. This issue has been detailed by me and other author^^-^*^ who feel that based on numerous clinical
332
Letter to the Editor
and pathologic parameters, as well as the exceedingly rare occurrence of laryngeal paragangliomas, that many if not all of these so-called malignant paragangliomas or metastasizing laryngeal paragangliomas are, in fact, neuroendocrine carcinomas that have been erroneously diagnosed as p a r a g a n g l i ~ m a s . ~ - ~ This is further highlighted by the fact that the vast majority of malignant paragangliomas (as diagnosed by the presence of metastases) primarily arise in the retroperitoneum and in relation to the vagal body.6 In Dr. Moisa’s description of laryngeal paragangliomas, he notes the cell nest (Zellballen) pattern surrounded by fibrovascular stroma as characteristic of paragangliomas. This is true. However, this histology is not pathognomonic for paragangliomas. The identical patterns, as well as cytomorphologic appearances are seen in neuroendocrine tumors of the larynx.324 Dr. Moisa describes the immunocytochemical findings identified in the three neoplastic groups he proposes; however, the antigenic profile cited does not differentiate any of these neoplasms. In fact, there is much overlap in the immunocytochemical reactivity of neuroendocrine tumors in general. Paragangliomas have characteristic staining of the peripherally located sustentacular cells by S-100 protein, a fact not detailed by Dr. Moisa. Along these lines, the author cites neurospecific enolase [the appropriate nomenclature for this antibody is neuron-specific enolase (NSE)] as being the most representative marker for neuroendocrine tumors. This is erroneous and further highlights the absence of an acceptable literature search. Among pathologists, NSE is often sarcastically referred to as “nonspecific” enolase emphasizing the fact that this antibody cross reacts with cells of divergent histogenesis not only with neuroendocrine lesions. The most useful immunocytochemical marker in neuroendocrine lesions is chromogranin described in the early 1980~.~,’ Although Dr. Moisa does mention the controversy regarding the diagnosis of laryngeal paragangliomas in passing (page 503, third paragraph), to report the existence of 68 laryngeal paragangliomas- stating that laryngeal paragangliomas have a considerable
HEAD & NECK
July/August 1992
malignant potential with an indeterminate biologyand not to have detailed the argument surrounding this diagnosis as well as the evidence supporting the contention that the metastasizing and/or lethal laryngeal paragangliomas are neuroendocrine carcinomas, represents a misunderstanding of the subject as well as a less-than-exhaustive search into the subject matter. Finally, while paragangliomas are unquestionably neuroendocrine lesions, they should not be classified or categorized along with the laryngeal neuroendocrine carcinomas because of the differences in biologic behavior. I believe, as indicated above, that the article by Dr. Moisa contains numerous serious problems not the least important of which is the absence of an up-todate literature search. This flaw not only rests on the author’s shoulders, but the editorial staff of Head & Neck bears equally if not a greater share of the onus for the problems inherent in the article. Bruce M. Wenig, MD Department of Otolaryngic-Endocrine Pathology Armed Forces Institute of Pathology Washington DC 1. Moisa 11. Neuroendocrine tumors of the larynx. Head Neck 1991;13:498- 508. 2. Woodruff JM, Huvos AG, Erlandson FL4, Shah JP, Gerold
FP. Neuroendocrine carcinomas of the larynx: a study of two types, one of which mimics thyroid medullary carcinoma. Am J Surg Puthol 1985;9:771-790. 3. Wenig BM, Hyams VJ, Heffner DK. Moderately differentiated neuroendocrine carcinomas of the larynx: a clinicopathologic study of 54 cases. Cancer 1988;62:2658-2676. 4. Wenig BM, Gnepp DR. The spectrum of neuroendocrine carcinomas of the larynx. Sernin Diagn Pathol 1989;6:329-350. 5. Ferlito A, Friedmann I, Goldman NC. Primary carcinoid tumor of the larynx. ORL 1990;50:129-149. 6. Batsakis JG, ed. Paragangliomas of the head and neck. In:
Tumors of the head and neck: clinical and pathological considerations, 2nd ed. Baltimore: Williams & Wilkins Co., 1979:369-380. 7. Lloyd RV, Wilson BS. Specific endocrine tissue marker defined by a monoclonal antibody. Science 1983;222:628630. 8 . Wilson BS, Lloyd RV. Detection of chromogranin in neuroendocrine cells with a monoclonal antibody. Am J Pathol 1984;115:458-468.
REPLY:
I would like to thank Dr. Goepfert and the editorial staff of Head & Neck for allowing me to reply to Dr. Wenig’s remarks. Although I appreciate Dr. Wenig’s efforts to update us on the subject of laryngeal neuroendocrine neoplasms, most of his comments are inappropriate and inaccurate. My article’ was intended to organize an extensive, fragmented body of knowledge regarding laryngeal neoplasms demonstrating neuroendocrine differentiation. A review of the international literature was per-
Letter to the Editor
formed, along with several updates. The most current works on this topic a t the time my article was completed were published in 1987. Based on this, nomenclature, classification, and management suggestions were made. In contradistinction to previous reviews, paragangliomas of the larynx (PGL) were classified among the family of neuroendocrine tumors of the larynx (NETL). (This view is currently shared by the World Health Organization and other^.)^,^ Furthermore, unlike many previous reviews, the English as well as the non-English literature were considered. The statement regarding the comprehensive nature of my article regarding NETL appears justified. If my article may be faulted because of a lengthy period between its completion and the time of its submission for publication (July 20, 1990), I assume complete and exclusive responsibility for that. Despite this, the work does not possess the major flaws Dr. Wenig implies. Numerous works regarding laryngeal neuroendocrine neoplasms have appeared since I completed my review. Among the most important of these is a n edition of ORL devoted exclusively to this topic.2 Although there may not have been sufficient detailed information in the literature at the time of my original review‘ on which to base a definite differentiation between carcinoid and atypical carcinoid tumors of the larynx, there seems to be sufficient data upon which to make such a distinction a t the present time.4*5Accordingly, in light of additional material available after my original review was completed, our subsequent article reflected this distinction.6 Although Dr. Wenig has not missed the opportunity t o remind us of his own works, he has apparently not considered what is probably the premier collaborative work on NETL to As a result, most of his remarks are inaccurate. In view of this glaring omission, I find Dr. Wenig’s comments regarding the inadequacy of my review particularly inappropriate. Dr. Wenig states that “Laryngeal carcinoids are indolent neoplasms cured by surgical excision and there are no associated reported incidences of mortalities related to laryngeal carcinoid tumors” (paragraph two). This statement is incorrect. In a recent update of 13 patients with this neoplasm, four patients developed distant metastasis, whereas one patient died of disease. The authors noted that “Typical laryngeal carcinoids are less aggressive than their atypical counterparts but late distant metastasis and death may O C C U ~ . ” ~ Because my review was not intended as an exhaustive histopathologic description of PGL or of the other NETL, such descriptions having been provided by others, this topic was adequately addressed and sufficiently referenced (page 501I.l Contrary to Dr. Wenig’s impression, no attempt was made to suggest a pathognomonic histologic description of PGL. As such, Dr. Wenig’s statements in this matter are inaccurate. The issue regarding the clinical behavior of PGL remains controversial. I addressed this issue appropri-
HEAD & NECK
JulyiAugust 1992
333
ately, citing authors who were of the opinion that PGL are essentially benign and that malignant PGL probably represent misdiagnosed lesions, as well as authors who felt PGL could demonstrate malignant behavior (page 503).’ Some recent workers have noted an incidence of metastatic disease and mortality among PGL similar to my f i g ~ r e s .Although ~ these authors addressed the issue that some malignant PGL reported in the literature may indeed represent misdiagnosed lesions, they nevertheless wisely concluded that “A true estimate of the malignant potential and prognosis of the laryngeal paraganglioma awaits improvements in diagnostic techniques.”’ Others, however, have noted a 3% incidence of malignancy among PGL, concluding that most malignant PGL are in reality atypical carcinoids that may have been misdiagnosed.’ Greater awareness, more precise diagnosis, and closer follow-up of patients with PGL should help to resolve this controversy in the future. At present, however, the most prudent approach may be to consider PGL as mostly benign while possessing a malignant potential, as I have suggested (page 505).l The overlapping ultrastructural and cytochemical characteristics among NETL is obvious from Table 3 (page 5011.l No attempt was made to distinguish between the various NETL based on these features. Therefore, I see no reason for Dr. Wenig’s negative remarks in this matter as he is in agreement with me. The relevance of Table 3,l however, is to demonstrate those features unique to NETL as a group, features that may be used to distinguish NETL as a family of tumors from other laryngeal neoplasms. Dr. Wenig seems to have missed this crucial point entirely. The section entitled “Future Goals” (pages 504- 505)’ addresses the issues of neuroendocrine markers. Contrary to Dr. Wenig’s impression, no suggestion is made to indicate that NSE is a pathognomonic marker for all NETL, since no PGL at the time of my review had been tested for this substance (Table 3).l In fact, I begin the last paragraph of that section by stating that “. . . a characteristic marker for NETL has not been conclusively identified . . .” (page 5051.’ Dr. Wenig’s contention that PGL should not be classified along with the other NETL is contrary to current opinion. The neuroendocrine nature of PGL
334
Letter to the Editor
based on ultrastructural and cytochemical features is obvious.’,’ Furthermore, Dr. Wenig states that “paragangliomas are unquestionably neuroendocrine lesions” (paragraph three, last sentence). Finally, and probably most importantly, the nomenclature “paraganglioma of the larynx” and the inclusion of this neoplasm in the classification of neuroendocrine neoplasms of the larynx (as I proposed)’ have been recently suggested by the World Health organization To’ ’ exclude this tumor and numerous a ~ t h o r i t i e s . ~ ’ ~ from a classification of NETL demonstrates a lessthan-thorough appreciation regarding the entire spectrum of laryngeal neuroendocrine neoplasms. My original suggestions were based on the literature available at the time my review was completed.’ The topic of laryngeal neuroendocrine neoplasms has evolved in recent years, yet many of my proposals have apparently remained appropriate. In fact, many of these recommendations seem to have been independently accepted by others.233 ldel 1. Moisa, M D Department of Otolaryngology
Montefiore Medical Center Bronx, NY
1. Moisa 11. Neuroendocrine tumors of the larynx. Head Neck
1991;13:498-508. 2. ORL, Journal for Oto-Rhino-Laryngology and Its Related Specialties, vol. 53. Basel, Switzerland S. Karger,
1991:185-264.
3. Ferlito A, Rosai J. Terminology and classification of neuroendocrine neoplasms of the larynx. ORL J Otorhino-
laryngol Relat Spec 1991;53:185-187. 4. El-Naggar AK, Batsakis JG. Carcinoid tumor of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:188- 193. 5 . Woodruff JM, Senie RT. Atypical carcinoid tumor of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:194-209. 6. Moisa 11, Silver CE. Treatment of neuroendocrine neoplasms of the larynx. ORL J Otorhinolaryngol Relat Spec 1991;53:259-264. 7. Konowitz PM, Lawson W, Som PM, Urken ML, Breakstone BA, Biller HF. Laryngeal paraganglioma: update on diagnosis and treatment. Laryngoscope 1988;98:40-49. 8. Barnes L. Paraganglioma of the larynx. A critical review of the literature. ORL J Otorhinolaryngol Relat Spec 1991;53:220-234.
HEAD & NECK
July/August 1992
