- Email: [email protected]
A case of schwannoma presenting as a benign parotid tumor
Egyptian Journal of Ear, Nose, Throat and Allied Sciences (2014) xxx, xxx–xxx
Egyptian Society of Ear, Nose, Throat and Allied Sciences
Egyptian Journal of Ear, Nose, Throat and Allied Sciences www.ejentas.com
CASE REPORT
A case of schwannoma presenting as a benign parotid tumor Noha Abdel Hakam 1, Ismail Farag *, George Philip
2
Hamad Medical Corporation, Doha, Qatar Received 26 April 2014; accepted 10 May 2014
KEYWORDS Parotid; Schwannoma
Abstract Schwannoma is a benign, capsulated perineural tumor of neuroectodermal derivation that originates from the Schwann cells of the neural sheath of motor and sensory peripheral nerves. Its etiology is still unknown. The tumor is usually solitary, smooth surfaced, slow growing and generally asymptomatic. Intraparotid schwannomas are uncommon. The benign tumors of neurogenic origin should be considered in the differential diagnosis of parotid region masses. A case of parotid schwannoma is described with review of literature. The case is of interest due to the relative rarity of the pathology and presence of non significant symptoms for a presumed initial clinical diagnosis. ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
1. Introduction Schwannomas referred to as neurilemomas or neurinomas are benign, capsulated tumors of neuroectodermal derivation that originate from Schwann cells of neural sheath of motor and sensory peripheral nerves: the etiology is still unknown.1 Schwannoma can occur either as a component of genetic conditions, such as neurofibromatosis type I (NF1) and II (NF2), or as sporadic neoplasms.2 25% to 45% of all schwannomas occur in the head and neck, mostly affecting the eighth cranial * Corresponding author. Mobile: +974 5506387. E-mail addresses: [email protected] (N.A. Hakam), ifarag@ hotmail.com (I. Farag), [email protected] (G. Philip). 1 Address: P.O. Box 3050 Doha, Qatar. Mobile: +974 77018208. 2 Mobile: +974 55012792. Peer review under responsibility of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
Production and hosting by Elsevier
nerve (acoustic neurinoma).3 A symptomatic swelling of the parotid gland is the main complaint in cases of parotid schwannoma. It is very difficult to preoperatively diagnose parotid schwannomas because their incidence is very rare. 0.2–1.5% of all parotid tumors rarely produce any signs and symptoms.4 2. Case description A seventeen year old Pakistani female presented with left sided infrauricular swelling noticed more than 5 years back, slowly increasing in size, not associated with pain. Examination revealed left sided well localized infrauricular swelling of about 4 · 3 cm, mobile not attached to overlying skin, non tender, facial nerve functions being normal. She was otherwise fit and healthy. Laboratory tests were within normal limits .Fine needle aspiration was non conclusive. CT scan showed a large well defined, hypodense, soft tissue mass lesion inferior to the superficial lobe of the left parotid gland, it causes focal bulge of the overlying skin contour and measures about 3.7 · 2 · 2.6 cm at its maximum height and
2090-0740 ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences. http://dx.doi.org/10.1016/j.ejenta.2014.05.002 Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002
2
N.A. Hakam et al.
Figure 1
Head CT-scan, axial cut showing mass arising from left parotid gland.
cross sectional diameter. No significant enhancement was seen in post contrast study, no calcification could be detected within it. Multilevel small cervical lymphnodes were noted in the neck (Fig. 1). Patient underwent surgery, the mass was exposed through classical parotidectomy incision and was excised with the superficial lobe of the parotid gland. The well encapsulated mass was not in direct relation with the facial nerve or its branches. The histopathology examination revealed normal parotid tissue and multinodular neural lesion with features of schwannoma (Figs. 2a and 2b). Postoperatively there was no facial paresis. The patient had normal facial expressions (Fig. 3). 3. Discussion Schwannomas or neurogenic tumors of salivary glands are very rare. Intraparotid schwannomas present as a slowly growing non tender parotid swelling without facial weakness.
Figure 2a
Histopathology of schwannoma (H&E ·40).
Figure 2b
Histopathology of schwannoma (H&E ·100).
Most authors5,6 find it difficult to establish a correct preoperative diagnosis of facial nerve neuroma. Coleney and Janeeka reviewed seventeen patients with twenty-three neurilemmomas of facial nerve and in only three cases a correct preoperative diagnosis was made.5 Fine needle aspiration cytology (FNAC) has a high diagnostic specificity in parotid tumors. Balle and Graisen7 reported two cases of schwannoma who had FNAC performed a total of five times, four of these were non diagnostic, while in fifth there was a suspicion of adenolymphoma. In our case FNAC was non conclusive. CT scan was done and it showed non significant enhancement, so FNAC and CT scan failed to diagnose the specific pathology preoperatively. Literature review shows that the rate of facial nerve palsy at time of diagnosis is low and more than 75% of intraparotid facial nerve schwannomas remain unknown until surgery. In the present case the tumor was easily excised and it was not attached to the facial nerve trunk or any of its branches, usually, neurolemmomas arise from main trunk or branches of facial nerve as they course through parotid gland.
Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002
Schwannoma as benign parotid tumor
Figure 3
(a and b) Post operative physical examination showing intact left facial nerve.
Rarely, the tumor might be found to have no relation with facial nerve or its branches.8 Neurolemmomas of the lateral region of the neck are frequently not found to be associated with any large nerve, as reported by Puteney et al. and Kragh et al. who emphasized this point.9,10 They found that the nerve of origin was identified in only 22 out of 80 cases of neurilemmomas of lateral cervical region. Das et al., investigated 136 cases of solitary schwannomas of the head and neck region. They found only 10 lesions in the parotid region and in the majority of their cases, and the nerve of origin could not be ascertained.11 4. Conclusion Report of a case of schwannoma mimicking benign parotid tumor in a young female is presented. The tumor was treated successfully with excision and there are no post operative complications. Though rare, the possibility of schwannomas should also be included in this differential diagnosis of benign parotid lumps. Conflict of interest
3
References 1. Stout AP. Atlas of Tumor Pathology. Tumors of the Peripheral Nervous System. Section II Fascide 6. Washington, DC: AFIP; 1949, 15–16. 2. Mrugala MM, Batchelor TT, Plotkin SR. Peripheral and cranial nerve sheath tumors. Curr Opin Neurol. 2005;18:604–610. 3. Das Gupta TK, Brasfield RD, Strong EW, Hajdu SA. Benign solitary schwannomas (neurilemomas). Cancer. 1969;24:355–366. 4. O’Donoghue GM, Brackmann DE, House JW, Jackler RK. Neuromas of the facial nerve. Am J Otol. 1989;10(1):49–54. 5. Conley J, Janeeka I. Neurilemmoma of facial nerve. J Plast Reconstr Surg. 1973;52:55–60. 6. Lin SR, Go EB. Neurilemmoma of facial nerve. Neuroradiology. 1973;6:185–187. 7. Balle VH, Graison C. Neurilemmomas of facial nerve presenting as parotid tumors. Ann olorhinolaryngol. 1984;93:79. 8. Helidonis E, Dokianakis G, Pantazopoulas PA. Schwannoma of parotid gland. J Laryngol. 1978;XCII(8):833. 9. Putney FJ, Moran JJ, Thomas GK. Neurogenic tumours of head and neck. Laryngoscope. 1964;74:1037–1059. 10. Kragh LV, Soule LH, Masson JK. Benign and malignant neurilemmomas of head and neck. Surg Gynecol Obstet. 1960;III:211. 11. Das Gupta TK, Brasfiedl RD, Strong EW. Hajdu I–II. Benign solitary schwannomas. Cancer. 1969;24:355.
None.
Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002
Egyptian Society of Ear, Nose, Throat and Allied Sciences
Egyptian Journal of Ear, Nose, Throat and Allied Sciences www.ejentas.com
CASE REPORT
A case of schwannoma presenting as a benign parotid tumor Noha Abdel Hakam 1, Ismail Farag *, George Philip
2
Hamad Medical Corporation, Doha, Qatar Received 26 April 2014; accepted 10 May 2014
KEYWORDS Parotid; Schwannoma
Abstract Schwannoma is a benign, capsulated perineural tumor of neuroectodermal derivation that originates from the Schwann cells of the neural sheath of motor and sensory peripheral nerves. Its etiology is still unknown. The tumor is usually solitary, smooth surfaced, slow growing and generally asymptomatic. Intraparotid schwannomas are uncommon. The benign tumors of neurogenic origin should be considered in the differential diagnosis of parotid region masses. A case of parotid schwannoma is described with review of literature. The case is of interest due to the relative rarity of the pathology and presence of non significant symptoms for a presumed initial clinical diagnosis. ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
1. Introduction Schwannomas referred to as neurilemomas or neurinomas are benign, capsulated tumors of neuroectodermal derivation that originate from Schwann cells of neural sheath of motor and sensory peripheral nerves: the etiology is still unknown.1 Schwannoma can occur either as a component of genetic conditions, such as neurofibromatosis type I (NF1) and II (NF2), or as sporadic neoplasms.2 25% to 45% of all schwannomas occur in the head and neck, mostly affecting the eighth cranial * Corresponding author. Mobile: +974 5506387. E-mail addresses: [email protected] (N.A. Hakam), ifarag@ hotmail.com (I. Farag), [email protected] (G. Philip). 1 Address: P.O. Box 3050 Doha, Qatar. Mobile: +974 77018208. 2 Mobile: +974 55012792. Peer review under responsibility of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
Production and hosting by Elsevier
nerve (acoustic neurinoma).3 A symptomatic swelling of the parotid gland is the main complaint in cases of parotid schwannoma. It is very difficult to preoperatively diagnose parotid schwannomas because their incidence is very rare. 0.2–1.5% of all parotid tumors rarely produce any signs and symptoms.4 2. Case description A seventeen year old Pakistani female presented with left sided infrauricular swelling noticed more than 5 years back, slowly increasing in size, not associated with pain. Examination revealed left sided well localized infrauricular swelling of about 4 · 3 cm, mobile not attached to overlying skin, non tender, facial nerve functions being normal. She was otherwise fit and healthy. Laboratory tests were within normal limits .Fine needle aspiration was non conclusive. CT scan showed a large well defined, hypodense, soft tissue mass lesion inferior to the superficial lobe of the left parotid gland, it causes focal bulge of the overlying skin contour and measures about 3.7 · 2 · 2.6 cm at its maximum height and
2090-0740 ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences. http://dx.doi.org/10.1016/j.ejenta.2014.05.002 Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002
2
N.A. Hakam et al.
Figure 1
Head CT-scan, axial cut showing mass arising from left parotid gland.
cross sectional diameter. No significant enhancement was seen in post contrast study, no calcification could be detected within it. Multilevel small cervical lymphnodes were noted in the neck (Fig. 1). Patient underwent surgery, the mass was exposed through classical parotidectomy incision and was excised with the superficial lobe of the parotid gland. The well encapsulated mass was not in direct relation with the facial nerve or its branches. The histopathology examination revealed normal parotid tissue and multinodular neural lesion with features of schwannoma (Figs. 2a and 2b). Postoperatively there was no facial paresis. The patient had normal facial expressions (Fig. 3). 3. Discussion Schwannomas or neurogenic tumors of salivary glands are very rare. Intraparotid schwannomas present as a slowly growing non tender parotid swelling without facial weakness.
Figure 2a
Histopathology of schwannoma (H&E ·40).
Figure 2b
Histopathology of schwannoma (H&E ·100).
Most authors5,6 find it difficult to establish a correct preoperative diagnosis of facial nerve neuroma. Coleney and Janeeka reviewed seventeen patients with twenty-three neurilemmomas of facial nerve and in only three cases a correct preoperative diagnosis was made.5 Fine needle aspiration cytology (FNAC) has a high diagnostic specificity in parotid tumors. Balle and Graisen7 reported two cases of schwannoma who had FNAC performed a total of five times, four of these were non diagnostic, while in fifth there was a suspicion of adenolymphoma. In our case FNAC was non conclusive. CT scan was done and it showed non significant enhancement, so FNAC and CT scan failed to diagnose the specific pathology preoperatively. Literature review shows that the rate of facial nerve palsy at time of diagnosis is low and more than 75% of intraparotid facial nerve schwannomas remain unknown until surgery. In the present case the tumor was easily excised and it was not attached to the facial nerve trunk or any of its branches, usually, neurolemmomas arise from main trunk or branches of facial nerve as they course through parotid gland.
Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002
Schwannoma as benign parotid tumor
Figure 3
(a and b) Post operative physical examination showing intact left facial nerve.
Rarely, the tumor might be found to have no relation with facial nerve or its branches.8 Neurolemmomas of the lateral region of the neck are frequently not found to be associated with any large nerve, as reported by Puteney et al. and Kragh et al. who emphasized this point.9,10 They found that the nerve of origin was identified in only 22 out of 80 cases of neurilemmomas of lateral cervical region. Das et al., investigated 136 cases of solitary schwannomas of the head and neck region. They found only 10 lesions in the parotid region and in the majority of their cases, and the nerve of origin could not be ascertained.11 4. Conclusion Report of a case of schwannoma mimicking benign parotid tumor in a young female is presented. The tumor was treated successfully with excision and there are no post operative complications. Though rare, the possibility of schwannomas should also be included in this differential diagnosis of benign parotid lumps. Conflict of interest
3
References 1. Stout AP. Atlas of Tumor Pathology. Tumors of the Peripheral Nervous System. Section II Fascide 6. Washington, DC: AFIP; 1949, 15–16. 2. Mrugala MM, Batchelor TT, Plotkin SR. Peripheral and cranial nerve sheath tumors. Curr Opin Neurol. 2005;18:604–610. 3. Das Gupta TK, Brasfield RD, Strong EW, Hajdu SA. Benign solitary schwannomas (neurilemomas). Cancer. 1969;24:355–366. 4. O’Donoghue GM, Brackmann DE, House JW, Jackler RK. Neuromas of the facial nerve. Am J Otol. 1989;10(1):49–54. 5. Conley J, Janeeka I. Neurilemmoma of facial nerve. J Plast Reconstr Surg. 1973;52:55–60. 6. Lin SR, Go EB. Neurilemmoma of facial nerve. Neuroradiology. 1973;6:185–187. 7. Balle VH, Graison C. Neurilemmomas of facial nerve presenting as parotid tumors. Ann olorhinolaryngol. 1984;93:79. 8. Helidonis E, Dokianakis G, Pantazopoulas PA. Schwannoma of parotid gland. J Laryngol. 1978;XCII(8):833. 9. Putney FJ, Moran JJ, Thomas GK. Neurogenic tumours of head and neck. Laryngoscope. 1964;74:1037–1059. 10. Kragh LV, Soule LH, Masson JK. Benign and malignant neurilemmomas of head and neck. Surg Gynecol Obstet. 1960;III:211. 11. Das Gupta TK, Brasfiedl RD, Strong EW. Hajdu I–II. Benign solitary schwannomas. Cancer. 1969;24:355.
None.
Please cite this article in press as: Hakam NA et al. A case of schwannoma presenting as a benign parotid tumor. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2014.05.002