- Email: [email protected]
A case of pleomorphic adenoma of the epiglottis
Auris Nasus Larynx 24 (1997) 303 – 307
A case of pleomorphic adenoma of the epiglottis Bilateral vocal-cord paralysis after YAG laser surgery Asako Ito *, Michihiko Sone, Yoko Kitamura, Shigeji Fukuta, Tsutomu Nakashima, Noriyuki Yanagita Department of Otorhinolaryngology, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466, Japan Received 21 October 1996; accepted 17 January 1997
Abstract Pleomorphic adenoma of the larynx is a rare disorder, and until recently has been treated mainly by approaches involving pharyngotomy. We encountered a case of pleomorphic adenoma originating from the laryngeal surface of the epiglottis and removed it using a YAG laser through a suspension laryngoscope. This case was complicated by delayed-onset bilateral vocal-cord paralysis, the causes of which are also discussed. © 1997 Elsevier Science Ireland Ltd. Keywords: Pleomorphic adenoma; Epiglottis; YAG laser; Bilateral vocal-cord paralysis
1. Introduction Most pleomorphic adenomas (benign mixed tumors) in otorhinolaryngological regions arise from major salivary glands, such as the parotid gland [1]. Their development in the minor salivary glands is rare, and despite the abundance of mi-
* Corresponding author. Tel.: + 81 52 7442323; fax: + 81 52 7442325.
nor salivary glands in the larynx, pleomorphic adenoma in this region is extremely rare; cases of pleomorphic adenoma located on the laryngeal surface of the epiglottis have been described only a few reports [2–5]. We encountered a case of pleomorphic adenoma originating from the laryngeal surface of the epiglottis and removed it using a YAG laser through a suspension laryngoscope. The present case was complicated by delayed-onset bilateral vocal-cord paralysis, which was treated successfully.
0385-8146/97/$17.00 © 1997 Elsevier Science Ireland Ltd. All rights reserved. PII S 0 3 8 5 - 8 1 4 6 ( 9 7 ) 0 0 0 4 7 - 3
304
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307
2. Case report A 79 year old woman presented at our hospital with a sensation of a lump in the throat that had persisted over the past 30 years. According to her memory, she had a history of an epiglottal tumor treated with radiation more than 30 years before, but the details of this were unclear. For the past several years, a ‘lumpy sensation’ had been worsening, and the woman was admitted because of dysphagia for solids. The patient had a history of hypertension and cerebral infarction, which were being treated by administration of nicardipine hydrochloride and dipyridamole. The patient had no history of smoking or alcohol usage. Indirect laryngoscopy found that a nodular, yellowish-white tumorous lesion with a smooth surface blocked the opening to the larynx form the laryngeal surface of the epiglottis. Laryngeal fiberscopic examination revealed that the tumor had not yet reached the vocal chink, and vocalcord movement was normal (Fig. 1). Plain neck X-ray (Fig. 2) and computed tomography (CT) scan examinations showed no abnormality at, or under the vocal chink and no swelling of the cervical lymph nodes. Biopsy was performed under local anesthesia, but the hardness of the tu-
Fig. 1. The laryngeal fiberscopic findings. The tumor was located slightly to the left-hand side on the laryngeal surface of the epiglottis. The surface of the tumor was yellowish-white, smooth, and nodular. It did not reached the vocal chink, and movement of the vocal cords appeared to be normal.
Fig. 2. The plain cervical X-ray. The tumor was located on the upper half of the epiglottis.
mor impeded collection of sufficient tissue for the diagnosis, an additional biopsy was required. The patient was hospitalized and surgery was performed using a contact Nd-YAG laser (Photon, LaserSonics Heraeus, LaserSonics, Japan) through a suspension laryngoscope under general anesthesia. The laser beam was emitted continuously at a maximum output of 30 W. Because of the broad-base configuration of the tumor, the excision surface was amply cauterized by the laser. No bleeding or edema was observed during the procedure, but in consideration of the advanced age of the patient and of post-operative complications, a tracheal cannula with an inner diameter of 4 mm (Mini Trach II®, Portex, UK) was inserted through thyrocricoid ligament to maintain the airway. This method is different from original tracheotomy, since respiration, voice and oral intake can be maintained. The tumor was arising from the upper half of the laryngeal of the epiglottis, presented a broad base and elastic rigidity, measured 2.0×1.5 cm, and was encapsulated. The sectioned surface was seen to be yellowish-white and nodular, yet uniform and substantial (Fig. 3). Histopathological findings resulted in a pleomorphic adenoma exhibiting a tumorous gland-duct architecture with a two-layer epithelial and myoepithelial structure (Fig. 4).
A. Ito et al. / Auris Nasus Larynx 24 (1997) 304–307
305
Fig. 3. The excised specimen. The tumor was elastically rigid, measured 2.0× 1.5 cm, and was encapsulated.
Fig. 5. The appearance of the laryngeal surface in the fifth month after surgery.
The postoperative course was satisfactory, with decannulation and oral intake beginning the next day. However, because respiratory distress appeared approximately 4 h after decannulation, and laryngeal fiberscopy revealed bilateral vocalcord paralysis (complete paralysis on the right side and incomplete paralysis on the left side), a tracheostomy was required the same day, No laryngeal edema was found at this time. Administration of ATP 80 mg by intravenous drip was
begun. Movement of the vocal cords appeared on the sixth day after the tracheotomy and replacement with a tracheal-opening retainer (Koken, Japan) was performed. Laryngeal fiberscopy and CT scan examinations confirmed the absence of granulation and constriction below the vocal chink, and on the twenty-first day after the operation the tracheal-opening retainer was removed and the patient was discharged. Flexible fiberscopic examination (Fig. 5) 5 months after surgery showed the excised surface of the tumor to exhibit cicatrization and disappearance of fur, and no signs of recurrence were seen. Bilateral movement of the vocal cords appeared to be normal.
3. Discussion
Fig. 4. The histopathological findings. A gland-duct architecture composed of a two-layer structure having epithelial and myoepithelial components (H and E; original magnification × 200).
Pleomorphic adenoma of the larynx is an extremely rare disorder, with only 14 cases reported in western literature in the past 30 years. The majority of cases, including the present case, were located on the epiglottis; five of eight cases were located on the laryngeal surface [2–5]. The remaining three cases were located on the lingual surface [6–8] (Table 1). Because this tumor is generally considers to reveal latent malignant change, cases of which have also been reported [5,9], complete surgical
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307
306
removal (including the capsule) is believed to be best, and until recently pharyngotomy had primarily been performed. However, some cases have also required partial epiglottectomy, and cases which have accordingly taken an unfortunate turn have also been reported [4]. An approach by pharyngotomy has been believed to be of utility from the standpoint of complete removal including the capsule under visualization of the entire tumor [10], but use of a laser is thought to be possible when the tumor is of small size and the area of attachment to the epiglottis can be visualized. Use of laser methods enables excision with no danger of dispersion or survival of tumor cells. Use of a laser also results in less bleeding and edema, and avoids the profuse postoperative glanulation, cicatrization, or scar formation [8,11] obtained good results using a CO2 laser on a pleomorphic adenoma located on the lingual surface of the epiglottis, and laser surgery was preformed in the present case as well, we used a contact Nd-YAG laser, which offers excellent Table 1 Pleomorphic adenoma of the larynx cases reported in the past 30 years
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 a
Authors
Year
Location
Terracol [15] Aboulker and Demaldent [16] Sabri and Hajjar [9]a Leroux-Robert [17] Jokinen et al. [2] Pinel et al. [6] Cotelingam et al. [3] Som et al. [18] Tobin [4] Zakzouk [19] Hunt McMillan and Fechner [20] Milford et al. [5]a Baptista et al. [7] Suttner et al. [8] Ito et al.
1965 1965
Vocal cord Vocal cord
1967
Vocal cord
1968
Subglottis
1974 1975 1977
Vocal cord Epiglottis Epiglottis
1976 1981 1985 1986
Ary-epiglott Epiglottis Subglottis Ventric, band
1989
Epiglottis
1992 1992 Present study
Epiglottis Epiglottis Epiglottis
Malignant changes arising in the pleomorphic adenoma.
characteristics in terms of coagulation, less bleeding and controllability of incisions. The present case was also complicated by bilateral vocal-cord paralysis on the second day after the operation. Vocal-cord paralysis after intubation is said to occur generally at a frequency of one every 1800 cases, but most cases of such paralysis are on the left side due to the course of the recurrent nerve, and also bilateral paralysis is extremely rare. Causative factors mainly seen to include the use of an unsuitable endotracheal tube, excessive cuff inflation and compression of stretching of the recurrent nerve due to extension of the neck [12–14]. Possible causes of parlaysis in the present case include the use of a metal endotracheal tube for laser surgery, edema in surrounding tissue due to intubation of the Mini Trach II, advanced age, and hyperextension of the cervical vertebrae. The Mini Trach II was inserted out of concern of postoperative complications due to patient’s age, but findings during the procedure indicated that preventive tracheotomy was not necessary. In conclusion, the authors have reported on a rare case of pleomorphic adenoma of the epiglottis witch appeared to have existed for more than 30 years; it was possible to excise this tumor buccally using a YAG laser without preforming epiglottectomy. This case was also complicated by the unusual experience of bilateral vocal-cord paralysis occurring postoperatively, and so a discussion of the related literature has been added.
References [1] Batsakis JG. Tumors of the major salivary glands. Tumours of the head and neck. Clinical and pathological considerations. Second edition, Ch. 1. Baltimore: Williams and Wilkins, 1979;1 – 75. [2] Jokinen K, Seppala A, Palva A. Laryngeal ryngeal pleomorphic adenoma. J Laryngol Otol 1974;36:1131 – 4. [3] Cotelingam JD, Barnes L, Nixon VB. Pleomorphic adenoma of the epiglottis. Arch Otolaryngol 1977;103:245 – 7. [4] Tobin HA. Mixed tumor of the epiglottis. Case report. Otolaryngol Head Neck Surg 1981;89:953 – 5. [5] Milford, C. A., Mugliston TA, O’Flynn P, McCarthy K. Carcinoma arising in a pleomorphic adenoma of the epiglottis. J Laryngol Otol 1989;103:324 – 7.
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307 [6] Pinel PJ, Trotoux J, Vilde F, Arnoux Y. Tumeur mixte de l’piglotte. Ann Otol Rhinol Laryngol Chir Cervicofac 1975;92:692 – 5. [7] Baptista PM, Garcia-Tapia R, Vazquez JJ. Pleomorphic adenoma of the epiglottis. J Otolaryngol 1992;21:355–7. [8] Suttner HJ, Sto¨ß H, Iro H. Pleomorphes adenoma der epiglottis. HNO 1992;40:453–5. [9] Sabri JA, Hajjar MA. Malignant mixed tumor of the vocal cord. Arch Otolaryngol 1967;85:332–4. [10] Kleinsasser O. Tumoren des larynx und des hypopharynx. Stuttgart: Thieme. 1987. [11] Ohyama M, Katsuda K, Nobori T, Yamamoto M, Furuta S, et al. Treatment of head and neck tumors by contact Nd-YAG laser surgery. Auris Nasus Larynx (Tokyo) 1985;12:138 – 42. [12] Holley HS, Gildea JE. Vocal cord paralysis after tracheal intubation. JAMA 1971;215:281–4. [13] Nuutinen J, Ka¨rja¨ J. Bilateral vocal cord paralysis follow-
.
307
ing general anesthesia. Laryngoscope 1981;91:83 – 6. [14] Cox RH, Welborn SG. Vocal cord paralysis after endotracheal anesthesia. South Med J 1981;74:1258 – 60. [15] Terracol J. Les tumeurs salivaires dites mixtes dularynx. Ann Otol Rhinol Laryngol (Paris) 1965;82(12):959 – 60. [16] Aboulker P, DeeeP., Deeemaldemaldent JE. Tumeur mixte du larynx. Ann Otol Rhinol Laryngol (Paris) 1966;83(1 – 2):89 – 90. [17] Leroux-Robert J. Tumeurs dites mixtes (ou epitheliomas a stroma remanie) parotidiennes et non parotidiennes. Ann Otol. Rhinol Laryngol (Paris) 1968;85 (8):753 – 770. [18] Som PM, Nagel BD, Feuerstein SS, Strauss L. Benign pleomorphic adenoma of the larynx. A case report. Ann Otol 1979;88:112 – 5. [19] Zakzouk MS. Pleomorphic adenoma of the larynx. J Laryngol Otol 1985;99:611 – 3. [20] Hunt McMillan III R, Fechner RE. Pleomorphic adenoma of the larynx. Arch Patol Lab Med 1986;110(3):245 – 7.
.
A case of pleomorphic adenoma of the epiglottis Bilateral vocal-cord paralysis after YAG laser surgery Asako Ito *, Michihiko Sone, Yoko Kitamura, Shigeji Fukuta, Tsutomu Nakashima, Noriyuki Yanagita Department of Otorhinolaryngology, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466, Japan Received 21 October 1996; accepted 17 January 1997
Abstract Pleomorphic adenoma of the larynx is a rare disorder, and until recently has been treated mainly by approaches involving pharyngotomy. We encountered a case of pleomorphic adenoma originating from the laryngeal surface of the epiglottis and removed it using a YAG laser through a suspension laryngoscope. This case was complicated by delayed-onset bilateral vocal-cord paralysis, the causes of which are also discussed. © 1997 Elsevier Science Ireland Ltd. Keywords: Pleomorphic adenoma; Epiglottis; YAG laser; Bilateral vocal-cord paralysis
1. Introduction Most pleomorphic adenomas (benign mixed tumors) in otorhinolaryngological regions arise from major salivary glands, such as the parotid gland [1]. Their development in the minor salivary glands is rare, and despite the abundance of mi-
* Corresponding author. Tel.: + 81 52 7442323; fax: + 81 52 7442325.
nor salivary glands in the larynx, pleomorphic adenoma in this region is extremely rare; cases of pleomorphic adenoma located on the laryngeal surface of the epiglottis have been described only a few reports [2–5]. We encountered a case of pleomorphic adenoma originating from the laryngeal surface of the epiglottis and removed it using a YAG laser through a suspension laryngoscope. The present case was complicated by delayed-onset bilateral vocal-cord paralysis, which was treated successfully.
0385-8146/97/$17.00 © 1997 Elsevier Science Ireland Ltd. All rights reserved. PII S 0 3 8 5 - 8 1 4 6 ( 9 7 ) 0 0 0 4 7 - 3
304
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307
2. Case report A 79 year old woman presented at our hospital with a sensation of a lump in the throat that had persisted over the past 30 years. According to her memory, she had a history of an epiglottal tumor treated with radiation more than 30 years before, but the details of this were unclear. For the past several years, a ‘lumpy sensation’ had been worsening, and the woman was admitted because of dysphagia for solids. The patient had a history of hypertension and cerebral infarction, which were being treated by administration of nicardipine hydrochloride and dipyridamole. The patient had no history of smoking or alcohol usage. Indirect laryngoscopy found that a nodular, yellowish-white tumorous lesion with a smooth surface blocked the opening to the larynx form the laryngeal surface of the epiglottis. Laryngeal fiberscopic examination revealed that the tumor had not yet reached the vocal chink, and vocalcord movement was normal (Fig. 1). Plain neck X-ray (Fig. 2) and computed tomography (CT) scan examinations showed no abnormality at, or under the vocal chink and no swelling of the cervical lymph nodes. Biopsy was performed under local anesthesia, but the hardness of the tu-
Fig. 1. The laryngeal fiberscopic findings. The tumor was located slightly to the left-hand side on the laryngeal surface of the epiglottis. The surface of the tumor was yellowish-white, smooth, and nodular. It did not reached the vocal chink, and movement of the vocal cords appeared to be normal.
Fig. 2. The plain cervical X-ray. The tumor was located on the upper half of the epiglottis.
mor impeded collection of sufficient tissue for the diagnosis, an additional biopsy was required. The patient was hospitalized and surgery was performed using a contact Nd-YAG laser (Photon, LaserSonics Heraeus, LaserSonics, Japan) through a suspension laryngoscope under general anesthesia. The laser beam was emitted continuously at a maximum output of 30 W. Because of the broad-base configuration of the tumor, the excision surface was amply cauterized by the laser. No bleeding or edema was observed during the procedure, but in consideration of the advanced age of the patient and of post-operative complications, a tracheal cannula with an inner diameter of 4 mm (Mini Trach II®, Portex, UK) was inserted through thyrocricoid ligament to maintain the airway. This method is different from original tracheotomy, since respiration, voice and oral intake can be maintained. The tumor was arising from the upper half of the laryngeal of the epiglottis, presented a broad base and elastic rigidity, measured 2.0×1.5 cm, and was encapsulated. The sectioned surface was seen to be yellowish-white and nodular, yet uniform and substantial (Fig. 3). Histopathological findings resulted in a pleomorphic adenoma exhibiting a tumorous gland-duct architecture with a two-layer epithelial and myoepithelial structure (Fig. 4).
A. Ito et al. / Auris Nasus Larynx 24 (1997) 304–307
305
Fig. 3. The excised specimen. The tumor was elastically rigid, measured 2.0× 1.5 cm, and was encapsulated.
Fig. 5. The appearance of the laryngeal surface in the fifth month after surgery.
The postoperative course was satisfactory, with decannulation and oral intake beginning the next day. However, because respiratory distress appeared approximately 4 h after decannulation, and laryngeal fiberscopy revealed bilateral vocalcord paralysis (complete paralysis on the right side and incomplete paralysis on the left side), a tracheostomy was required the same day, No laryngeal edema was found at this time. Administration of ATP 80 mg by intravenous drip was
begun. Movement of the vocal cords appeared on the sixth day after the tracheotomy and replacement with a tracheal-opening retainer (Koken, Japan) was performed. Laryngeal fiberscopy and CT scan examinations confirmed the absence of granulation and constriction below the vocal chink, and on the twenty-first day after the operation the tracheal-opening retainer was removed and the patient was discharged. Flexible fiberscopic examination (Fig. 5) 5 months after surgery showed the excised surface of the tumor to exhibit cicatrization and disappearance of fur, and no signs of recurrence were seen. Bilateral movement of the vocal cords appeared to be normal.
3. Discussion
Fig. 4. The histopathological findings. A gland-duct architecture composed of a two-layer structure having epithelial and myoepithelial components (H and E; original magnification × 200).
Pleomorphic adenoma of the larynx is an extremely rare disorder, with only 14 cases reported in western literature in the past 30 years. The majority of cases, including the present case, were located on the epiglottis; five of eight cases were located on the laryngeal surface [2–5]. The remaining three cases were located on the lingual surface [6–8] (Table 1). Because this tumor is generally considers to reveal latent malignant change, cases of which have also been reported [5,9], complete surgical
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307
306
removal (including the capsule) is believed to be best, and until recently pharyngotomy had primarily been performed. However, some cases have also required partial epiglottectomy, and cases which have accordingly taken an unfortunate turn have also been reported [4]. An approach by pharyngotomy has been believed to be of utility from the standpoint of complete removal including the capsule under visualization of the entire tumor [10], but use of a laser is thought to be possible when the tumor is of small size and the area of attachment to the epiglottis can be visualized. Use of laser methods enables excision with no danger of dispersion or survival of tumor cells. Use of a laser also results in less bleeding and edema, and avoids the profuse postoperative glanulation, cicatrization, or scar formation [8,11] obtained good results using a CO2 laser on a pleomorphic adenoma located on the lingual surface of the epiglottis, and laser surgery was preformed in the present case as well, we used a contact Nd-YAG laser, which offers excellent Table 1 Pleomorphic adenoma of the larynx cases reported in the past 30 years
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 a
Authors
Year
Location
Terracol [15] Aboulker and Demaldent [16] Sabri and Hajjar [9]a Leroux-Robert [17] Jokinen et al. [2] Pinel et al. [6] Cotelingam et al. [3] Som et al. [18] Tobin [4] Zakzouk [19] Hunt McMillan and Fechner [20] Milford et al. [5]a Baptista et al. [7] Suttner et al. [8] Ito et al.
1965 1965
Vocal cord Vocal cord
1967
Vocal cord
1968
Subglottis
1974 1975 1977
Vocal cord Epiglottis Epiglottis
1976 1981 1985 1986
Ary-epiglott Epiglottis Subglottis Ventric, band
1989
Epiglottis
1992 1992 Present study
Epiglottis Epiglottis Epiglottis
Malignant changes arising in the pleomorphic adenoma.
characteristics in terms of coagulation, less bleeding and controllability of incisions. The present case was also complicated by bilateral vocal-cord paralysis on the second day after the operation. Vocal-cord paralysis after intubation is said to occur generally at a frequency of one every 1800 cases, but most cases of such paralysis are on the left side due to the course of the recurrent nerve, and also bilateral paralysis is extremely rare. Causative factors mainly seen to include the use of an unsuitable endotracheal tube, excessive cuff inflation and compression of stretching of the recurrent nerve due to extension of the neck [12–14]. Possible causes of parlaysis in the present case include the use of a metal endotracheal tube for laser surgery, edema in surrounding tissue due to intubation of the Mini Trach II, advanced age, and hyperextension of the cervical vertebrae. The Mini Trach II was inserted out of concern of postoperative complications due to patient’s age, but findings during the procedure indicated that preventive tracheotomy was not necessary. In conclusion, the authors have reported on a rare case of pleomorphic adenoma of the epiglottis witch appeared to have existed for more than 30 years; it was possible to excise this tumor buccally using a YAG laser without preforming epiglottectomy. This case was also complicated by the unusual experience of bilateral vocal-cord paralysis occurring postoperatively, and so a discussion of the related literature has been added.
References [1] Batsakis JG. Tumors of the major salivary glands. Tumours of the head and neck. Clinical and pathological considerations. Second edition, Ch. 1. Baltimore: Williams and Wilkins, 1979;1 – 75. [2] Jokinen K, Seppala A, Palva A. Laryngeal ryngeal pleomorphic adenoma. J Laryngol Otol 1974;36:1131 – 4. [3] Cotelingam JD, Barnes L, Nixon VB. Pleomorphic adenoma of the epiglottis. Arch Otolaryngol 1977;103:245 – 7. [4] Tobin HA. Mixed tumor of the epiglottis. Case report. Otolaryngol Head Neck Surg 1981;89:953 – 5. [5] Milford, C. A., Mugliston TA, O’Flynn P, McCarthy K. Carcinoma arising in a pleomorphic adenoma of the epiglottis. J Laryngol Otol 1989;103:324 – 7.
A. Ito et al. / Auris Nasus Larynx 24 (1997) 303–307 [6] Pinel PJ, Trotoux J, Vilde F, Arnoux Y. Tumeur mixte de l’piglotte. Ann Otol Rhinol Laryngol Chir Cervicofac 1975;92:692 – 5. [7] Baptista PM, Garcia-Tapia R, Vazquez JJ. Pleomorphic adenoma of the epiglottis. J Otolaryngol 1992;21:355–7. [8] Suttner HJ, Sto¨ß H, Iro H. Pleomorphes adenoma der epiglottis. HNO 1992;40:453–5. [9] Sabri JA, Hajjar MA. Malignant mixed tumor of the vocal cord. Arch Otolaryngol 1967;85:332–4. [10] Kleinsasser O. Tumoren des larynx und des hypopharynx. Stuttgart: Thieme. 1987. [11] Ohyama M, Katsuda K, Nobori T, Yamamoto M, Furuta S, et al. Treatment of head and neck tumors by contact Nd-YAG laser surgery. Auris Nasus Larynx (Tokyo) 1985;12:138 – 42. [12] Holley HS, Gildea JE. Vocal cord paralysis after tracheal intubation. JAMA 1971;215:281–4. [13] Nuutinen J, Ka¨rja¨ J. Bilateral vocal cord paralysis follow-
.
307
ing general anesthesia. Laryngoscope 1981;91:83 – 6. [14] Cox RH, Welborn SG. Vocal cord paralysis after endotracheal anesthesia. South Med J 1981;74:1258 – 60. [15] Terracol J. Les tumeurs salivaires dites mixtes dularynx. Ann Otol Rhinol Laryngol (Paris) 1965;82(12):959 – 60. [16] Aboulker P, DeeeP., Deeemaldemaldent JE. Tumeur mixte du larynx. Ann Otol Rhinol Laryngol (Paris) 1966;83(1 – 2):89 – 90. [17] Leroux-Robert J. Tumeurs dites mixtes (ou epitheliomas a stroma remanie) parotidiennes et non parotidiennes. Ann Otol. Rhinol Laryngol (Paris) 1968;85 (8):753 – 770. [18] Som PM, Nagel BD, Feuerstein SS, Strauss L. Benign pleomorphic adenoma of the larynx. A case report. Ann Otol 1979;88:112 – 5. [19] Zakzouk MS. Pleomorphic adenoma of the larynx. J Laryngol Otol 1985;99:611 – 3. [20] Hunt McMillan III R, Fechner RE. Pleomorphic adenoma of the larynx. Arch Patol Lab Med 1986;110(3):245 – 7.
.