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Pediatric tumors of the parapharyngeal space
International Journal of Pediatric Otorhinolaryngology (2004) 68, 601—606
CASE REPORT
Pediatric tumors of the parapharyngeal space Three case reports and a literature review Ivo Stárek a,*, Vladim´ır Mihál b , Zbynˇ ek Novák b , Dagmar Posp´ıšilová b , Jaroslav Vomᡠcka c , Jan Vokurka d a
ENT Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic Pediatric Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic c Radiology Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic d ENT Clinic, Faculty Hospital, Sokolská 408, 500 05 Hradec Králové, Czech Republic b
Received 22 October 2003 ; received in revised form 4 December 2003; accepted 5 December 2003
KEYWORDS Parapharyngeal space; Tumor; Children
Summary Three cases of pediatric primary parapharyngeal space tumors, namely a Burkitt’s lymphoma, lipoblastoma and a ganglioneuroma are described here, along with a literature review. These disorders are very rare, accounting for less than 20% of all parapharyngeal neoplasms. In comparison to adults, there are differences in pathomorphologic spectrum of pediatric parapharyngeal tumors. The authors describe the prevalence of malignant tumors, mainly soft tissues sarcomas. The salivary gland tumors and paragangliomas which dominate in adult populations, are extremely rare in pediatric populations where the most common benign tumor to be encountered is that of neurogenic origin. It follows that these features modify the diagnostic and therapeutic approach. © 2003 Elsevier Ireland Ltd. All rights reserved.
1. Introduction The parapharyngeal space (PPS) is a triangular fat-filled compartment of the neck, lying lateral to the pharynx. It is described as an inverted pyramid with the base at the skull and apex at the great hyoid cornu. The styloid process along with the attaching muscles and tensor veli palatini fascia divide the PPS into a prestyloid and retrostyloid compartment. The former contains external carotid and ascending pharyngeal artery, deep parotid lobe and minor submucous and dysontogenic salivary glands. The contents of the latter are created by
* Corresponding author. Tel.: +420-58-585-4608; fax: +420-58-585-2158. E-mail address: [email protected] (I. St´ arek).
the IX, X, XI and XII cranial nerves, cervical sympathetic chain, internal jugular vein, internal carotid artery and lymph nodes. This anatomic complexity is responsible for a wide variety of tumors, arising from the PPS. In adult populations, tumors of the PPS account for no more than 0.5% of all head and neck neoplasms [1]. This group of neoplasms consists of primary lesions, direct tumor extensions from adjacent regions and metastatic diseases. Primary disorders include salivary gland tumors (50%), neurogenic tumors such as paragangliomas, schwannomas and neurofibromas (30%). The remaining (20%) of the broad histopathologic spectrum of parapharyngeal neoplasms is made up of an array of soft tissue lesions (lipomas, leiomyomas, teratomas, rhabdomyosarcomas, fibrosarcomas, malignant lymphomas, etc.). Nearly 80% of these tumors are
0165-5876/$ — see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2003.12.007
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benign, represented mostly by a pleomorphic adenoma [2]. Compared to adults, parapharyngeal space in pediatric pathology, inflammation prevails. This originates mostly from infected para- and retropharyngeal lymph nodes. Parapharyngeal tumors in patients younger than 18 years are very rare. It is especially in this age group that the maximal therapeutic effect must be achieved with minimal morbidity. For this reason, the diagnostic and surgical challenge these tumors are associated with are much more delicate than in adult populations. In the current study three cases of primary parapharyngeal tumor in children and a literature review are presented.
10 female patients. Six of 20 (30%) adults neoplasms were malignant, and 14 (70%) were benign. Three of 23 (13%) patients belonged to the pediatric group (less than 18 years).
3. Case reports 1. A 4-year-old boy with a 3-day history of odynophagia presented to the pediatrician. On clinical examination the right lateral pharyngeal wall and the tonsil were displaced medially. In spite of the absence of fever, the patient was diagnosed with paratonsillar abscess. An incision through the anterior faucial pillar revealed only blood. Chest X-ray, abdominal ultrasonography and laboratory findings were within normal limits. A contrast CT was performed revealing a large (40 mm × 33 mm) homogenous hypodense mass with minimal enhancement in the right parapharyngeal space (Fig. 1). Fine needle aspiration biopsy was not performed. The patient was indicated for cervical excision. During the surgery, the lower pole of the
2. Material and methods In a 15-year period, a total of 23 cases of primary parapharyngeal tumors were identified at the ENT Clinic in Olomouc and Hradec Králové. The main clinical and pathological characteristics of these patients are listed in Table 1. There were 13 male and
Table 1 Characteristics of 23 patients with parapharyngeal space tumors in current study Characteristics no.
n = 23 Age
Sex
Diagnosis
Adult tumors 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
54 63 21 48 74 65 19 40 50 40 68 46 34 47 30 55 30 42 63 58
M M M M M F F M F M F F M F F M M M M F
Squamous cell carcinoma Adenocarcinoma NOS Primitive neurectodermal tumor Pleomorphic adenoma Adenoid cystic carcinoma Pleomorphic adenoma Adenoid cystic carcinoma Neurofibroma Carotid body tumor Pleomorphic adenoma Vagal paraganglioma Musculoaponeurotic fibromatosis Solitary fibrous tumor bg Carotid body tumor Neurofibroma Neuroma Carotid body tumor Neuroma Vagal paraganglioma Malignant neuroma pediatric tumors
Pediatric tumors 21 22 23
4y 9 mo 2y
M F F
Burkitt’s lymphoma Lipoblastic lipoma Ganglioneuroma
y y y y y y y y y y y y y y y y y y y y
M: male, F: female, y: years, mo: months.
Pediatric tumors of the parapharyngeal space
Fig. 1 Parapharyngeal Burkitt’s lymphoma (bars). Axial CT scan. Internal carotid artery and internal jugular vein are displaced slightly posteriorly (arrow). Position of the right tonsil is indicated by a curved arrow.
tumor was easily exposed but finger dissection was impossible due to the firm adherence of the lesion to the walls of the PPS. Frozen section revealed a Burkitt’s lymphoma and the operation was discontinued. Histopathologic diagnosis was subsequently confirmed by a definitive histopathologic examination of the specimen. The wound healing was uneventful. The patient received chemotherapy according to the BFM NHL 95 protocol. Forty two months after finishing the treatment, the boy is alive, with no evidence of disease. 2. A 9-month-old girl developed an asymptomatic mass behind the angle of the left mandible. Examination revealed a non-tender soft swelling, bulging in the upper part of the neck. All other clinical and laboratory findings were within normal limits. A MRI showed a large tumor in the left PPS. The non-enhancing lesion had a high signal intensity on T1-weighted images (Fig. 2), and an intermediate signal intensity on T2 images. Both the clinical and radiological features led to a provisional diagnosis of lipoma. A complete resection of the tumor was performed by a cervical-parotid approach. The postoperative course was complicated by slight paresis of the marginal branch of the facial nerve, receding within 3 weeks. Histopathologic examination of the removed specimen revealed the characteristic pattern of a benign lipoblastic lipoma. On follow-up 1 year postoperatively, the girl did well and there was no clinical or MRI evidence of residual or recurrent tumor.
603
Fig. 2 Parapharyngeal lipoblastic lipoma. Axial MRI scan, gadolinium-enhanced T1 W image. A large tumor (bars) fills the parapharyngeal space, the compressed parotid gland is seen as a thin rim at the lateral aspect of the lesion (arrow).
3. A 2-year-old girl was seen for a mass localized high on the right side of neck that had been growing asymptomatically for 2 months. Intraorally, the right posterior pharyngeal wall was displaced anteromedially. The were no signs of any cranial nerve impairment. A CT scan revealed a retrostyloid tumor sized
Fig. 3 Parapharyngeal ganglioneuroma. Axial enhanced CT scan. A hypodense, slightly inhomogenous mass (bars) closely contacts laterally displaced internal carotid artery (arrow).
604 50 mm × 35 mm × 25 mm (Fig. 3). The tumor was completely removed using a cervical approach. The tumor was found to grow in the carotid triangle, with the upper pole extending close to the skull base. Postoperatively a transient right vocal cord paralysis was noted. Histopathologic examination revealed a benign ganglioneuroma. On 2-year-follow-up there are no signs of the tumor growth, the girl is doing well with no cranial or cervical sympathetic nerves dysfunction.
4. Discussion Parapharyngeal tumors in children are very rare, although their exact incidence is very difficult to determine. Most of them are referred as single case reports. In large studies in which the appropriate data are available, they make up 0—17% of all parapharyngeal neoplasms [2—9]. These numbers indicate that for many ENT surgeons these tumors are a sporadic curiosity. In a review of the literature, plus our report, 20 of 30 (67%) pediatric patients with primary parapharyngeal neoplasms (tumors growing from adjacent areas were excluded from this study) (see Table 2) were malignant. This strongly contrasts to adult tumors with only some 20—30% of cases represented by malignancy [2,3]. Albeit, our literature review has probably not been able to identify all primary pediatric parapharyngeal neoplasms that have ever occurred, in spite of the potential selection error, we assume that it truly reflects the reality, for salivary gland tumors, responsible for the prevalence of benign parapharyngeal lesions in adults, are encountered extremely rarely in children in this location. This corresponds well with the scarcity of pediatric major and minor salivary gland tumors, the majority of which are represented by hemangiomas and lymphangiomas, with epithelial lesions making up only 3% of all salivary tumors [10,11]. Moreover, benign paragangliomas, which account for up to 40% of all parapharyngeal tumors in adults [12], are also diagnosed very rarely in children [13]. The minimal occurrence of the above mentioned benign lesions in children makes the histopathologic spectrum of pediatric parapharyngeal neoplasms different from that of adults. The most common benign primary parapharyngeal tumor to be seen in children is thus not a pleomorphic adenoma, but a neoplasm of neurogenic origin, such as neurofibroma, neuroma and ganglioneuroma. From other non-malignant disorders, in analogy to the spectrum of pediatric head and neck tumors, lipoma,
I. St´ arek et al.
Table 2 Literature review and three current cases of pediatric primary parapharyngeal tumors
Ref.
Sex, age
Tumor type
[2] [3]
F, 17 y F, 12 y M, 9 y F, 17 y F, 14 y
Carotid paraganglioma Adenocarcinoma Adenocarcinoma Neurofibroma Malignant fibrous histiocytoma Rhabdomyosarcoma Neuroblastoma
[5] [9] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]
M, 17 y Sex not indicated, 3 mo M, 7 y F, 7 y M, 4 mo F, 8 y F, 3 mo F, 16 y F, 14 y F, 13 y M, 4 y Eight patients, age and sex not indicated F, neonate
[32] M, 2 mo [33] F, 18 mo Present study M, 4 y Present study F, 3 y Present study F, 13 mo
Burkitt’s lymphoma Chondrosarcoma Neurofibroma Rhabdomysarcoma Teratoma Vagal paraganglioma Ewing’s sarcoma Ganglioneuroma Chordoma Rhabdomyosarcoma Inflammatory myofibroblastic tumor Cystic hygroma Neuroblastoma Burkitt’s lymphoma Ganglioneuroma Lipoblastic lipoma
M: male, F: female, y: years, mo: months.
cystic hygroma, branchial cyst and vasoformative lesions are encountered relatively often. In the review (see Table 2) 17 out of 20 malignant lesions (85%) were represented by one chondrosarcoma, two lymphomas and 14 soft tissue sarcomas (neurogenic inclusive), out of which rhabdomyosarcoma was the most common (10/17). The remaining cases consisted of rare neoplasms, such as adenocarcinomas and chordoma. This distribution of malignant parapharyngeal affections correlates well with a comparison of malignant head and neck tumors in children in the three large series, reported by Jaffe [14]. In that study malignant soft tissue neoplasms and lymphomas represented an absolute majority of all head and neck malignancies, and only a minor part of the pathologic spectrum was created by an array of other histopathologic entities, originating from various head and neck tissues (melanomas, teratomas, parotid gland carcinomas, etc.).
Pediatric tumors of the parapharyngeal space Such a specific histopathologic spectrum of pediatric parapharyngeal tumors modifies their preoperative diagnosis and surgical treatment. Differential diagnosis is based on modern imaging methods, CT and MRI. These methods have a similar capacity for enabling reliable differentiation between hypervascular (i.e. paragangliomas, metastatic carcinomas, hemangiomas) and hypovascular lesions (salivary gland tumors, neurogenic tumors, lymphomas, sarcomas, etc.). Owing to the scarcity of tumors of the first group and salivary gland neoplasms in parapharyngeal space in children, differential diagnosis in most cases involves sarcomas, neurogenic neoplasms, lymphomas and an array of other more or less rare disorders. Unfortunately, all these lesions may share very similar or even the same radiologic features (density, homogeneity, signal intensity), making their confident differentiation impossible [15,16]. The only exceptions are lipomas and cysts with specific CT and MRI images. Another problem is that even a good MRI delineation of the tumor is not a reliable sign of benign process. Fine needle aspiration biopsy does not contribute significantly to the differential diagnosis of pediatric parapharyngeal lesions. In most cases peroperative biopsy, performed by an external approach at the beginning of the operation, is therefore necessary to establish histopathological diagnosis. Consequently, the operation is continued or finished if surgical disease or malignant lymphoma is confirmed, respectively. Multiple surgical approaches to solid parapharyngeal space tumors have been designed [1,2,7,17], the transoral approach being considered the least invasive. However due to a high complication rate and poor control of major vessels, most surgeons do not used it at all, while others use it exclusively only for small benign extraparotid tumors not palpable in the neck or parotid region [18]. Since such disorders are extremely rare in the parapharyngeal space in pediatric population, a transoral route is practically never indicated. The choice of external approaches is dictated by the tumor size, its location, relation to major vessels and assumed gravity. Nonetheless, a cervical-parotid approach is generally preferred, allowing relatively wide access to the parapharyngeal space, as in adults, even very large tumors can be removed this way. In less than 10% of all parapharyngeal tumors a mandibulotomy with tracheostomy must be performed [19]. In benign lesions this is necessary in voluminous pleomorphic adenomas to prevent the rupture of the capsule, in highly vascularized vagal and carotid paragangliomas and in tumors localized high at the skull base. Such neoplasms are extremely rare in children. A mandibulotomy, which must preferably be
605 avoided, will therefore hardly be necessary in the pediatric age group. In malignant tumors a mandibulotomy is usually performed to reach the tumor-free margins of the surrounding tissues. Unfortunately, given the anatomical complexity of the parapharyngeal space, in spite of every surgical effort, the prognosis of infiltratively growing lesions remains poor. In pediatric prevailing soft tissue sarcomas and neuroblastomas a new promising antineoplastic agent (Irinotecan) is now available [20]. The residual tumor can be therefore left behind both at the periphery of the lesions and around vital anatomic structures, such as internal carotid artery and cranial nerves. A mandibulotomy can be thus avoided, further minimizing surgical morbidity. In other malignant infiltratively growing lesions, especially extremely rare carcinomas, radical surgery with mandibulotomy remains an ethical dilemma. It must be solved individually taking into account other therapeutic options such as radiotherapy and chemotherapy.
References [1] P.M. Stell, A.O. Mansfeld, P.J. Stoney, Surgical approaches to tumors of the parapharyngeal space, Am. J. Otolaryngol. 6 (1985) 92—97. [2] K.D. Olsen, Tumors and surgery of the parapharyngeal space, Laryngoscope 104 (1994) 1—27. [3] A.G.D. Maran, I.J. Mackenzie, J.A.M. Murray, The parapharyngeal space, J. Laryngol. Otol. 98 (1984) 371—380. [4] K.P. Pang, Ch.H.K. Goh, H.M. Tan, Parapharyngeal space tumours: an 18 year review, J. Laryngol. Otol. 116 (2002) 170—175. [5] J.P. Windfuhr, K. Sesterhenn, Diagnostik und Zugangswege bei Tumoren des Parapharyngealraums–—Eine Übersicht, Laryngo-Rhino-Otologie 81 (2002) 797—806. [6] W. Work, R.L. Hybels, A study of tumors of the parapharyngeal space, Laryngoscope 84 (1974) 1748—1755. [7] M.L. Pensak, J.L. Gluckman, K.A. Shumrick, Parapharyngeal space tumors: an algorithm for evaluation and management, Laryngoscope 104 (1994) 1170—1173. [8] J.P. Malone, A. Agrawal, D.E. Schuller, Safety and efficacy of transcervical resection of parapharyngeal space neoplasms, Ann. Otol. Rhinol. Laryngol. 110 (2001) 1093— 1101. [9] Z.K. Szmeja, J. Laczkowksa-Przybylska, Pierwotne nowotwory przestreni przygardlowej w materiale Kliniki Otolaryngologii AM im. Marcinkowskiego w Poznaniu w latach 1993—1998, Otolaryngol. Pol. 53 (1999) 275—281. [10] D.L. Callender, R.B. Frankenthaler, M.A. Luna, S. Lee, M. Goepfert, Salivary gland neoplasms in children, Arch. Otolaryngol. Head Neck Surg. 118 (1992) 472—476. [11] A.M. Luna, J.G. Batsakis, A.K. El-Naggar, Salivary gland tumors in children, Ann. Otol. Rhinol. Laryngol. 100 (1991) 869—871. [12] R.L. Carrau, E.N. Myers, J.T. Johnson, Management of tumors arising in the parapharyngeal space, Laryngoscope 100 (1990) 583—589.
606 [13] L.P. Dehner, Head and neck, in: L.P. Dehner (Ed.), Pediatric Surgical Pathology, IInd ed., Williams and Wilkins, Baltimore, 1987, pp. 120—198. [14] B.F. Jaffe, Pediatric head and neck tumors: a study of 178 cases, Laryngoscope 83 (1973) 1644—1651. [15] P.M. Som, H.F. Biller, W. Lawson, M. Sacher, Ch.F. Lanzieri, Parapharyngeal space masses: an updated protocol based upon 104 cases, Radiology 153 (1984) 148—156. [16] P.M. Som, I.F. Braun, M.D. Shapiro, D.L. Reede, H.D. Curtin, R.A. Zimmerman, Tumors of the parapharyngeal space and upper neck: MR imaging characteristics, Radiology 164 (1984) 823—829. [17] J.P. Malone, A. Agrawal, D.E. Schuller, Safety and efficacy of transcervical resection of parapharyngeal space, Ann. Otol. Rhinol. Laryngol. 110 (2001) 1093—1098. [18] W.J. Goodwin, J.R. Chandler, Transoral excision of lateral parapharyngeal space tumors presenting intraorally, Laryngoscope 98 (1988) 266—269. [19] K.V. Hughes, K.D. Olsen, T.V. McCaffrey, Parapharyngeal space neoplasms, Head Neck 17 (1995) 124—130. [20] M. Cosetti, L.H. Wexler, E. Calejja, T. Trippett, M. LaQuaglia, A.G. Huvos, et al., Irinotecan for pediatric solid tumors: the memorial Sloan—Kettering experience, J. Pediatr. Hematol. Oncol. 24 (2002) 101—105. [21] S. Keiner, F. Bootz, U. Gütz, Parapharyngeal tumor beim Säugling, HNO 47 (1999) 828—829. [22] K. Moller-Andersen, A. Walsted, H. Broholm, Parapharyngeal Burkitt lymphoma in a seven-year-old boy, Ugsekrift Laeger 160 (1998) 4220—4221. [23] K.V. Suryanarayana, R. Balakrishnan, L. Rao, T.A. Rahim, Parapharyngeal space mesenchymal chondrosarcoma in childhood, Int. J. Pediatr. Otorhinolaryngol. 50 (1999) 69— 72.
I. St´ arek et al. [24] R.R. Cross, M.D. Shapiro, P.M. Som, MRI of the parapharyngeal space, Radiol. Clin. North. Am. 27 (1989) 353—378. [25] P.J. Gulllane, H.B. Lampe, R. Slinger, Erosive parapharyngeal space teratoma, J. Otolaryngol. 15 (1986) 317—321. [26] J.L. Netterville, G. Jackson, F. Miller, J.R. Wanamaker, M.E. Glasscock, Vagal paraganglioma: a review of 46 patients treated during a 20 year period, Arch. Otolaryngol. Head Neck Surg. 124 (1998) 1133—1140. [27] H. Singelmann, K. Bielefeld, O. Ebeling, Clinical manifestation of Ewing’s sarcoma as a retrotonsillar pharyngeal tumor, Laryngo-Rhino-Otologie 80 (2001) 161—165. [28] M.R. Kaufmann, J.S. Rhee, L.J. Fliegelman, P.D. Constantino, Ganglioneuroma of the parapharyngeal space in a pediatric patient, Otolaryngol. Head Neck Surg. 124 (2001) 702—704. [29] P.M. Bianchi, P. Marsella, R. Masi, G. Andriani, F.M. Tucci, P. Partipico, et al., Cervical chordoma in childhood: clinical statistical contribution, Int. J. Pediatr. Otorhinolaryngol. 18 (1989) 39—45. [30] W.W. Sutow, R.D. Lindberg, E.A. Gehan, A.H. Ragab, R.B. Raney, F. Ruymann, et al., Three-year relapse-free survival rates in childhood rhabdomyosarcoma of the head and neck, Cancer 49 (1982) 2217—2221. [31] A.M. Klein, S.R. Schoem, A. Altman, L. Eisenfeld, Inflammatory myofibroblastic tumor in the neonate: a case report, Otolaryngol. Head Neck Surg. 128 (2003) 145—147. [32] A. Kahn, D. Blum, A. Hoffman, M. Hamoir, D. Moulin, M. Spehl, et al., Obstructive sleep apnea induced by a parapharyngeal cystic hygroma in an infant, Sleep 8 (1985) 363—366. [33] J.H. Brandenburg, Symposium on malignancy. IV. Neurogenic tumors of the parapharyngeal space, Laryngoscope 82 (1972) 1292—1305.
CASE REPORT
Pediatric tumors of the parapharyngeal space Three case reports and a literature review Ivo Stárek a,*, Vladim´ır Mihál b , Zbynˇ ek Novák b , Dagmar Posp´ıšilová b , Jaroslav Vomᡠcka c , Jan Vokurka d a
ENT Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic Pediatric Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic c Radiology Clinic, Faculty Hospital, I.P.Pavlova 6, 775 20 Olomouc, Czech Republic d ENT Clinic, Faculty Hospital, Sokolská 408, 500 05 Hradec Králové, Czech Republic b
Received 22 October 2003 ; received in revised form 4 December 2003; accepted 5 December 2003
KEYWORDS Parapharyngeal space; Tumor; Children
Summary Three cases of pediatric primary parapharyngeal space tumors, namely a Burkitt’s lymphoma, lipoblastoma and a ganglioneuroma are described here, along with a literature review. These disorders are very rare, accounting for less than 20% of all parapharyngeal neoplasms. In comparison to adults, there are differences in pathomorphologic spectrum of pediatric parapharyngeal tumors. The authors describe the prevalence of malignant tumors, mainly soft tissues sarcomas. The salivary gland tumors and paragangliomas which dominate in adult populations, are extremely rare in pediatric populations where the most common benign tumor to be encountered is that of neurogenic origin. It follows that these features modify the diagnostic and therapeutic approach. © 2003 Elsevier Ireland Ltd. All rights reserved.
1. Introduction The parapharyngeal space (PPS) is a triangular fat-filled compartment of the neck, lying lateral to the pharynx. It is described as an inverted pyramid with the base at the skull and apex at the great hyoid cornu. The styloid process along with the attaching muscles and tensor veli palatini fascia divide the PPS into a prestyloid and retrostyloid compartment. The former contains external carotid and ascending pharyngeal artery, deep parotid lobe and minor submucous and dysontogenic salivary glands. The contents of the latter are created by
* Corresponding author. Tel.: +420-58-585-4608; fax: +420-58-585-2158. E-mail address: [email protected] (I. St´ arek).
the IX, X, XI and XII cranial nerves, cervical sympathetic chain, internal jugular vein, internal carotid artery and lymph nodes. This anatomic complexity is responsible for a wide variety of tumors, arising from the PPS. In adult populations, tumors of the PPS account for no more than 0.5% of all head and neck neoplasms [1]. This group of neoplasms consists of primary lesions, direct tumor extensions from adjacent regions and metastatic diseases. Primary disorders include salivary gland tumors (50%), neurogenic tumors such as paragangliomas, schwannomas and neurofibromas (30%). The remaining (20%) of the broad histopathologic spectrum of parapharyngeal neoplasms is made up of an array of soft tissue lesions (lipomas, leiomyomas, teratomas, rhabdomyosarcomas, fibrosarcomas, malignant lymphomas, etc.). Nearly 80% of these tumors are
0165-5876/$ — see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2003.12.007
602
I. St´ arek et al.
benign, represented mostly by a pleomorphic adenoma [2]. Compared to adults, parapharyngeal space in pediatric pathology, inflammation prevails. This originates mostly from infected para- and retropharyngeal lymph nodes. Parapharyngeal tumors in patients younger than 18 years are very rare. It is especially in this age group that the maximal therapeutic effect must be achieved with minimal morbidity. For this reason, the diagnostic and surgical challenge these tumors are associated with are much more delicate than in adult populations. In the current study three cases of primary parapharyngeal tumor in children and a literature review are presented.
10 female patients. Six of 20 (30%) adults neoplasms were malignant, and 14 (70%) were benign. Three of 23 (13%) patients belonged to the pediatric group (less than 18 years).
3. Case reports 1. A 4-year-old boy with a 3-day history of odynophagia presented to the pediatrician. On clinical examination the right lateral pharyngeal wall and the tonsil were displaced medially. In spite of the absence of fever, the patient was diagnosed with paratonsillar abscess. An incision through the anterior faucial pillar revealed only blood. Chest X-ray, abdominal ultrasonography and laboratory findings were within normal limits. A contrast CT was performed revealing a large (40 mm × 33 mm) homogenous hypodense mass with minimal enhancement in the right parapharyngeal space (Fig. 1). Fine needle aspiration biopsy was not performed. The patient was indicated for cervical excision. During the surgery, the lower pole of the
2. Material and methods In a 15-year period, a total of 23 cases of primary parapharyngeal tumors were identified at the ENT Clinic in Olomouc and Hradec Králové. The main clinical and pathological characteristics of these patients are listed in Table 1. There were 13 male and
Table 1 Characteristics of 23 patients with parapharyngeal space tumors in current study Characteristics no.
n = 23 Age
Sex
Diagnosis
Adult tumors 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
54 63 21 48 74 65 19 40 50 40 68 46 34 47 30 55 30 42 63 58
M M M M M F F M F M F F M F F M M M M F
Squamous cell carcinoma Adenocarcinoma NOS Primitive neurectodermal tumor Pleomorphic adenoma Adenoid cystic carcinoma Pleomorphic adenoma Adenoid cystic carcinoma Neurofibroma Carotid body tumor Pleomorphic adenoma Vagal paraganglioma Musculoaponeurotic fibromatosis Solitary fibrous tumor bg Carotid body tumor Neurofibroma Neuroma Carotid body tumor Neuroma Vagal paraganglioma Malignant neuroma pediatric tumors
Pediatric tumors 21 22 23
4y 9 mo 2y
M F F
Burkitt’s lymphoma Lipoblastic lipoma Ganglioneuroma
y y y y y y y y y y y y y y y y y y y y
M: male, F: female, y: years, mo: months.
Pediatric tumors of the parapharyngeal space
Fig. 1 Parapharyngeal Burkitt’s lymphoma (bars). Axial CT scan. Internal carotid artery and internal jugular vein are displaced slightly posteriorly (arrow). Position of the right tonsil is indicated by a curved arrow.
tumor was easily exposed but finger dissection was impossible due to the firm adherence of the lesion to the walls of the PPS. Frozen section revealed a Burkitt’s lymphoma and the operation was discontinued. Histopathologic diagnosis was subsequently confirmed by a definitive histopathologic examination of the specimen. The wound healing was uneventful. The patient received chemotherapy according to the BFM NHL 95 protocol. Forty two months after finishing the treatment, the boy is alive, with no evidence of disease. 2. A 9-month-old girl developed an asymptomatic mass behind the angle of the left mandible. Examination revealed a non-tender soft swelling, bulging in the upper part of the neck. All other clinical and laboratory findings were within normal limits. A MRI showed a large tumor in the left PPS. The non-enhancing lesion had a high signal intensity on T1-weighted images (Fig. 2), and an intermediate signal intensity on T2 images. Both the clinical and radiological features led to a provisional diagnosis of lipoma. A complete resection of the tumor was performed by a cervical-parotid approach. The postoperative course was complicated by slight paresis of the marginal branch of the facial nerve, receding within 3 weeks. Histopathologic examination of the removed specimen revealed the characteristic pattern of a benign lipoblastic lipoma. On follow-up 1 year postoperatively, the girl did well and there was no clinical or MRI evidence of residual or recurrent tumor.
603
Fig. 2 Parapharyngeal lipoblastic lipoma. Axial MRI scan, gadolinium-enhanced T1 W image. A large tumor (bars) fills the parapharyngeal space, the compressed parotid gland is seen as a thin rim at the lateral aspect of the lesion (arrow).
3. A 2-year-old girl was seen for a mass localized high on the right side of neck that had been growing asymptomatically for 2 months. Intraorally, the right posterior pharyngeal wall was displaced anteromedially. The were no signs of any cranial nerve impairment. A CT scan revealed a retrostyloid tumor sized
Fig. 3 Parapharyngeal ganglioneuroma. Axial enhanced CT scan. A hypodense, slightly inhomogenous mass (bars) closely contacts laterally displaced internal carotid artery (arrow).
604 50 mm × 35 mm × 25 mm (Fig. 3). The tumor was completely removed using a cervical approach. The tumor was found to grow in the carotid triangle, with the upper pole extending close to the skull base. Postoperatively a transient right vocal cord paralysis was noted. Histopathologic examination revealed a benign ganglioneuroma. On 2-year-follow-up there are no signs of the tumor growth, the girl is doing well with no cranial or cervical sympathetic nerves dysfunction.
4. Discussion Parapharyngeal tumors in children are very rare, although their exact incidence is very difficult to determine. Most of them are referred as single case reports. In large studies in which the appropriate data are available, they make up 0—17% of all parapharyngeal neoplasms [2—9]. These numbers indicate that for many ENT surgeons these tumors are a sporadic curiosity. In a review of the literature, plus our report, 20 of 30 (67%) pediatric patients with primary parapharyngeal neoplasms (tumors growing from adjacent areas were excluded from this study) (see Table 2) were malignant. This strongly contrasts to adult tumors with only some 20—30% of cases represented by malignancy [2,3]. Albeit, our literature review has probably not been able to identify all primary pediatric parapharyngeal neoplasms that have ever occurred, in spite of the potential selection error, we assume that it truly reflects the reality, for salivary gland tumors, responsible for the prevalence of benign parapharyngeal lesions in adults, are encountered extremely rarely in children in this location. This corresponds well with the scarcity of pediatric major and minor salivary gland tumors, the majority of which are represented by hemangiomas and lymphangiomas, with epithelial lesions making up only 3% of all salivary tumors [10,11]. Moreover, benign paragangliomas, which account for up to 40% of all parapharyngeal tumors in adults [12], are also diagnosed very rarely in children [13]. The minimal occurrence of the above mentioned benign lesions in children makes the histopathologic spectrum of pediatric parapharyngeal neoplasms different from that of adults. The most common benign primary parapharyngeal tumor to be seen in children is thus not a pleomorphic adenoma, but a neoplasm of neurogenic origin, such as neurofibroma, neuroma and ganglioneuroma. From other non-malignant disorders, in analogy to the spectrum of pediatric head and neck tumors, lipoma,
I. St´ arek et al.
Table 2 Literature review and three current cases of pediatric primary parapharyngeal tumors
Ref.
Sex, age
Tumor type
[2] [3]
F, 17 y F, 12 y M, 9 y F, 17 y F, 14 y
Carotid paraganglioma Adenocarcinoma Adenocarcinoma Neurofibroma Malignant fibrous histiocytoma Rhabdomyosarcoma Neuroblastoma
[5] [9] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]
M, 17 y Sex not indicated, 3 mo M, 7 y F, 7 y M, 4 mo F, 8 y F, 3 mo F, 16 y F, 14 y F, 13 y M, 4 y Eight patients, age and sex not indicated F, neonate
[32] M, 2 mo [33] F, 18 mo Present study M, 4 y Present study F, 3 y Present study F, 13 mo
Burkitt’s lymphoma Chondrosarcoma Neurofibroma Rhabdomysarcoma Teratoma Vagal paraganglioma Ewing’s sarcoma Ganglioneuroma Chordoma Rhabdomyosarcoma Inflammatory myofibroblastic tumor Cystic hygroma Neuroblastoma Burkitt’s lymphoma Ganglioneuroma Lipoblastic lipoma
M: male, F: female, y: years, mo: months.
cystic hygroma, branchial cyst and vasoformative lesions are encountered relatively often. In the review (see Table 2) 17 out of 20 malignant lesions (85%) were represented by one chondrosarcoma, two lymphomas and 14 soft tissue sarcomas (neurogenic inclusive), out of which rhabdomyosarcoma was the most common (10/17). The remaining cases consisted of rare neoplasms, such as adenocarcinomas and chordoma. This distribution of malignant parapharyngeal affections correlates well with a comparison of malignant head and neck tumors in children in the three large series, reported by Jaffe [14]. In that study malignant soft tissue neoplasms and lymphomas represented an absolute majority of all head and neck malignancies, and only a minor part of the pathologic spectrum was created by an array of other histopathologic entities, originating from various head and neck tissues (melanomas, teratomas, parotid gland carcinomas, etc.).
Pediatric tumors of the parapharyngeal space Such a specific histopathologic spectrum of pediatric parapharyngeal tumors modifies their preoperative diagnosis and surgical treatment. Differential diagnosis is based on modern imaging methods, CT and MRI. These methods have a similar capacity for enabling reliable differentiation between hypervascular (i.e. paragangliomas, metastatic carcinomas, hemangiomas) and hypovascular lesions (salivary gland tumors, neurogenic tumors, lymphomas, sarcomas, etc.). Owing to the scarcity of tumors of the first group and salivary gland neoplasms in parapharyngeal space in children, differential diagnosis in most cases involves sarcomas, neurogenic neoplasms, lymphomas and an array of other more or less rare disorders. Unfortunately, all these lesions may share very similar or even the same radiologic features (density, homogeneity, signal intensity), making their confident differentiation impossible [15,16]. The only exceptions are lipomas and cysts with specific CT and MRI images. Another problem is that even a good MRI delineation of the tumor is not a reliable sign of benign process. Fine needle aspiration biopsy does not contribute significantly to the differential diagnosis of pediatric parapharyngeal lesions. In most cases peroperative biopsy, performed by an external approach at the beginning of the operation, is therefore necessary to establish histopathological diagnosis. Consequently, the operation is continued or finished if surgical disease or malignant lymphoma is confirmed, respectively. Multiple surgical approaches to solid parapharyngeal space tumors have been designed [1,2,7,17], the transoral approach being considered the least invasive. However due to a high complication rate and poor control of major vessels, most surgeons do not used it at all, while others use it exclusively only for small benign extraparotid tumors not palpable in the neck or parotid region [18]. Since such disorders are extremely rare in the parapharyngeal space in pediatric population, a transoral route is practically never indicated. The choice of external approaches is dictated by the tumor size, its location, relation to major vessels and assumed gravity. Nonetheless, a cervical-parotid approach is generally preferred, allowing relatively wide access to the parapharyngeal space, as in adults, even very large tumors can be removed this way. In less than 10% of all parapharyngeal tumors a mandibulotomy with tracheostomy must be performed [19]. In benign lesions this is necessary in voluminous pleomorphic adenomas to prevent the rupture of the capsule, in highly vascularized vagal and carotid paragangliomas and in tumors localized high at the skull base. Such neoplasms are extremely rare in children. A mandibulotomy, which must preferably be
605 avoided, will therefore hardly be necessary in the pediatric age group. In malignant tumors a mandibulotomy is usually performed to reach the tumor-free margins of the surrounding tissues. Unfortunately, given the anatomical complexity of the parapharyngeal space, in spite of every surgical effort, the prognosis of infiltratively growing lesions remains poor. In pediatric prevailing soft tissue sarcomas and neuroblastomas a new promising antineoplastic agent (Irinotecan) is now available [20]. The residual tumor can be therefore left behind both at the periphery of the lesions and around vital anatomic structures, such as internal carotid artery and cranial nerves. A mandibulotomy can be thus avoided, further minimizing surgical morbidity. In other malignant infiltratively growing lesions, especially extremely rare carcinomas, radical surgery with mandibulotomy remains an ethical dilemma. It must be solved individually taking into account other therapeutic options such as radiotherapy and chemotherapy.
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