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Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report
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
Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report Ashwin Ashok Jaiswal *, Amrish Kumar Garg, Ravindranath Membally Department of ENT & Head Neck Surgery, J.L.N. Hospital & Research Centre, Sector 9, Bhilai (C.G), India Received 21 November 2013; accepted 13 December 2013
KEYWORDS Pleomorphic adenoma; Salivary gland tumors; Salivary gland neoplasms; Total parotidectomy
Abstract Pleomorphic adenoma is the most common type of all salivary gland tumors, involving more frequently the parotid gland. In most series, it represents 45–75% of all salivary gland neoplasms. We report an unusual case of a huge tumor that measured 9 · 8 cm & 400 g by weight with extensive bone formation, occurring in the parotid gland of a 22 year old man. Thorough clinical examination was done. FNAC was done which showed Myxochondroid matrix with glandular epithelial cells suggesting pleomorphic adenoma. CT scan head & neck revealed a large mass with nodular areas of calcification within soft tissue with marked narrowing of orophayngeal lumen. Total parotidectomy with preservation of facial nerve was done by the Transcervical Transparotid approach. The histopathological findings suggested the possibility of extensive endochondral ossification in pleomorphic adenoma. Preservation of facial nerve functions is a key to successful parotid surgery. ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
1. Introduction About 70% of all salivary gland tumors arise in the parotid gland, and approximately 85% are benign. Pleomorphic adenoma (PA) is the most common benign salivary gland * Corresponding author. Address: Department of ENT & Head Neck Surgery, J.L.N. Hospital & Research Centre, Sector 9, Bhilai, Dist. Durg, Chhattisgarh 490009, India. Tel.: +91 9407983605; fax: +91 0788 2227814. E-mail address: [email protected] (A.A. Jaiswal). Peer review under responsibility of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
Production and hosting by Elsevier
tumor that exhibits a wide cytomorphologic and architectural diversity. It is also known as ‘‘Mixed tumor, salivary gland type’’. The annual incidence is approximately 2–3.5 cases per 100,000 population. This paper describes a case of a huge pleomorphic adenoma arising in the parotid gland with extensive bone formation and treated by total parotidectomy with facial nerve preservation. 2. Case profile A 22 year old male patient presented to OPD of the Department of ENT & Head Neck Surgery, J.L.N. Hospital &Research Centre, Bhilai, with gradually progressive swelling below the left ear since 3 years and difficulty in swallowing since 3 months. On examination, diffuse swelling was seen over the left parotid region extending to the upper part of the neck,
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.2013.12.005
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
2 the skin over the swelling was stretched with no visible pulsations. On palpation it was non tender, hard in consistency, the skin over the swelling was free. On intraoral examination, a smooth bulge was seen on the soft palate & lateral pharyngeal wall. There were no pathologic lymph nodes in the neck. FNAC was done which showed Myxochondroid matrix with glandular epithelial cells suggesting pleomorphic adenoma (Fig. 1). Taking into consideration its consistency & extent a contrast enhanced CT scan head & neck was done which showed a large mass seen at the angle of the mandible occupying the left parapharyngeal space with large nodular areas of calcification within soft tissue with marked narrowing of oropharyngeal lumen (Fig. 2). MRI revealed a large mass of heterogenous texture with multiple soft tissue densities & hypo intense areas with narrowing of oropharyngeal lumen (Fig. 3). Total parotidectomy with preservation of facial nerve was done by the Trancervical Transparotid approach. Excised tumor of size 9 · 8 cm & 400 g by weight was sent for HPE. Grossly cut section showed extensive bone formation (Fig. 4). Histopathological examination showed benign epithelial component in close proximity to cartilage predominance of cartilaginous matrix with enchondral ossification, trabeculae of bone showed bone marrow like structure (Fig. 5). Immunohistochemistry revealed small cells surrounding bony areas positive for S-100 and CK HMW, suggests myoepithelial cells (Fig. 6). The postoperative course was uneventful & facial nerve functions were normal.
A.A. Jaiswal et al.
Figure 2 MRI scan showing a large mass with obliteration of oropharyngeal lumen.
3. Discussion Pleomorphic adenoma (PA) represents 45–74% of all salivary gland tumors and 65% of them occur in the parotid gland.1–3 PA is the most common in third to sixth decades; the average age at presentation is between 43 and 46 years. PA has a slight female predominance.4,5 PA frequently manifests with focal or partial ossified and calcified degeneration but PA of the
Figure 3 FNAC; Myxochondroid matrix along with epithelial cells (MGG, ·40).
Figure 4 Gross specimen showing extensive bony & cartilaginous areas, hard & gritty to cut. Figure 1 CT scan axial view showing a large mass seen at the angle of mandible with large nodular areas of calcification within soft tissue.
parotid gland with extensive bone formation is a rare entity & very few cases have been mentioned in the literature.6,7
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report
Figure 5 H & E, ·40 shows extensive areas of bone formation within cartilage.
Figure 6 cells).
IHC showing positivity for CK HMW (Myoepithelial
Pleomorphic adenoma usually presents as a slow-growing, painless mass, which may be present for many years. Symptoms and signs depend on the location.8 In the parotid, 90% occur in the superficial lobe and most commonly are seen in the tail of the gland. Pleomorphic adenoma in the deep lobe of the parotid gland may present as an oral retrotonsillar mass or parapharyngeal space tumor; indeed, tumors arising at this site are the source of the most common parapharyngeal space tumors. Patients with minor salivary gland tumors may present with a variety of symptoms, depending on the site of the tumor; such symptoms include dysphagia, dyspnea, hoarseness, difficulty in chewing, and epistaxis. In our case pt. presented with gradually progressive swelling along with difficulty in swallowing. The firmness of pleomorphic adenoma varies with the nature & amount of stromal component. So it ranges from soft in the case of more mucinous tumors to hard in tumors with extensive chondroid or collagenous component. In our case, it was hard in consistency due to extensive bone formation. The diagnosis of salivary gland tumors utilizes both tissue sampling and radiographic studies. Tissue sampling proce-
3
dures include fine needle aspiration (FNA) and core needle biopsy (bigger needle comparing to FNA). Both of these procedures can be done in an outpatient setting. In our case FNAC suggested the diagnosis of pleomorphic adenoma. Diagnostic imaging techniques for salivary gland tumors include ultrasound, computer tomography (CT) and magnetic resonance imaging (MRI). CT is excellent for demonstrating bony invasion. MRI provides superior soft tissue delineation such as perineural invasion when compared to CT only.9 Histopathologically, PA shows a remarkable degree of morphology diversity. The essential components are the capsule, epithelial and myoepithelial cells, and mesenchymal or stromal elements.10 The mesenchymal-like component is mucoid/myxoid, cartilaginous, or hyalinized. Focal or partial ossified and calcified degeneration is occasionally seen in PA, but extensive ossified and calcified degeneration as seen in our case is extremely rare. Shi et al. & Shigeishi et al. have described pleomorphic adenoma with extensive bone formation but a tumor of size 9 · 8 cm & 400 g by weight with such extensive bone formation has not been mentioned in the literature. Akasaka et al. suggested that ossification in benign mixed tumors indicates development from pluripotent stem cells.11 Lee et al. in their case report suggested that the bony matrix appears to be deposited directly by metaplastic myoepithelial cells rather than through enchondral ossification.12 As the outcome of the study of Harrison,13 calcification in PA was found in a lumen and in epithelial cells and consisted of needleshaped crystals that contained calcium and phosphorus and were probably apatite; and small collections of crystals in the lumen, which were often associated with membranous cellular debris, appeared to form larger calcified masses by fusion. In most instances, the diagnosis of pleomorphic adenoma is made through a straightforward microscopic identification. However, immunohistochemistry (IHC) may be supportive and helpful in delineating the different cell types and components, as well as in differentiating pleomorphic adenoma from other tumors.14–16 In our case IHC revealed small cells surrounding bony areas positive for S-100 and CK HMW, suggests myoepithelial cells. Treatment of pleomorphic adenomas is a complete surgical excision with a surrounding margin of normal tissue, i.e., superficial/total parotidectomy with facial nerve preservation, submandibular gland excision or wide local excision for a minor salivary gland. Simple enucleation of these tumors is what is believed to have led to high local recurrence rates in the past and should be avoided. Rupture of the capsule and tumor spillage in the wound are also believed to increase the risk of recurrence, so meticulous dissection is paramount.17–20 In our case a total parotidectomy with preservation of facial nerve was done. 4. Summary Pleomorphic adenoma (PA) is the most common benign salivary gland tumor but extensive bone formation in it is extremely rare. FNAC plays an important role in the diagnosis of pleomorphic adenoma. CT scan is helpful in diagnosis, knowing the extent of tumor & calcification status.
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
4 Surgical excision i.e., superficial/total parotidectomy with preservation of facial nerve is a primary modality of treatment. HPE & IHC are helpful for confirmation of diagnosis.
5. Conflict of interest None.
References 1. Ellis GL, Auclair PL, eds. Atlas of tumor pathology. Tumours of the salivary glands. Washington, DC: Armed Forces Institute of Pathology; 1995:39–41. 2. Speight PM, Barrett AW. Salivary gland tumours. Oral Dis. 2002;8(5):229–240. 3. Ledesma-Montes C, Garces-Ortiz M. Salivary gland tumours in a Mexican sample. A retrospective study. Med Oral. 2002;7(5):324–330. 4. Eveson JW, Cawson RA. Salivary gland tumours: a review of 2410 cases with particular reference to histological types, site, age and sex distribution. J Pathol. 1985;146:51–58. 5. Waldron CA, el Mofty SK, Gnepp DR. Tumors of the intraoral minor salivary glands: a demographic and histologic study of 426 cases. Oral Surg Oral Med Oral Pathol. 1988;66:323–333. 6. Shi H, Wang P, Wang S, Yu Q. Pleomorphic adenoma with extensive ossified and calcified degeneration: unusual CT findings in one case. AJNR Am J Neuroradiol. 2008;29(4):737–738. 7. Shigeishi H, Hayashi K, Takata T, Kuniyasu H, Ishikawa T, Yasui W. Pleomorphic adenoma of the parotid gland with extensive bone formation. Pathol Int. 2001;51(11):883–886. 8. Spiro RH. Salivary neoplasms: overview of a 35-year experience with 2807 patients. Head Neck Surg. 1986;8(3):177–184.
A.A. Jaiswal et al. 9. Koyuncu M, Sesßen T, Akan H, et al. Comparison of computed tomography and magnetic resonance imaging in the diagnosis of parotid tumors. Otolaryngol Head Neck Surg. 2003;129(6):726–732. 10. Barnes L, Eveson JW, Reichart P, et al., eds. World Health Organization classification of tumours: pathology and genetics of head and neck tumours. Lyon, France: IARC Press; 2005:254–258. 11. Akasaka T, Ondera H, Matsuta M. Cutaneous mixed tumour containing ossification, hair matrix, and sebaceous ductal differentiation. J Dermatol. 1997;24:125–131. 12. Lee KC, Chan JKC, Chong YW. Ossifying pleomorphic adenoma of the maxillary antrum. J Laryngol Otol. 1992;106:50–52. 13. Harrison JD. Ultrastructural observation of calcification in a pleomorphic adenoma of the parotid gland. Ultrastruct Pathol. 1991;152:185–188. 14. Kusafuka K, Yamaguchi A, Kayano T, Takemura T. Immunohistochemical localization of the bone morphogenetic protein-6 in salivary pleomorphic adenomas. Pathol Int. 1999;49(12): 1023–1027. 15. Nishimura T, Furukawa M, Kawahara E, Miwa A. Differential diagnosis of pleomorphic adenoma by immunohistochemical means. J Laryngol Otol. 1991;105(12):1057–1060. 16. Stead RH, Qizilbash AH, Kontozoglou T, Daya AD, Riddell RH. An immunohistochemical study of pleomorphic adenomas of the salivary gland: glial fibrillary acidic protein-like immunoreactivity identifies a major myoepithelial component. Hum Pathol. 1988;19(1):32–40. 17. Ellis GL, Auclair PL, Gnepp DR, eds. Surgical pathology of the salivary glands. Philadelphia: WB Saunders; 1991. 18. Eisele DW, Johns ME. Salivary gland neoplasms. In: Bailey BJ, ed. Head & neck surgery-otolaryngology. Philadelphia: Lippincott Williams & Wilkins; 2001:1279–1297. 19. Seifert G, Miehlke A, Haubrich J, Chilla R, eds. Diseases of the salivary glands. New York: Thieme Inc.; 1986. 20. Califano JC, Eisele DW. Benign salivary gland neoplasms. Otolaryngol Clin North Am. 1999;35(5):861–873.
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
Egyptian Society of Ear, Nose, Throat and Allied Sciences
Egyptian Journal of Ear, Nose, Throat and Allied Sciences www.ejentas.com
CASE REPORT
Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report Ashwin Ashok Jaiswal *, Amrish Kumar Garg, Ravindranath Membally Department of ENT & Head Neck Surgery, J.L.N. Hospital & Research Centre, Sector 9, Bhilai (C.G), India Received 21 November 2013; accepted 13 December 2013
KEYWORDS Pleomorphic adenoma; Salivary gland tumors; Salivary gland neoplasms; Total parotidectomy
Abstract Pleomorphic adenoma is the most common type of all salivary gland tumors, involving more frequently the parotid gland. In most series, it represents 45–75% of all salivary gland neoplasms. We report an unusual case of a huge tumor that measured 9 · 8 cm & 400 g by weight with extensive bone formation, occurring in the parotid gland of a 22 year old man. Thorough clinical examination was done. FNAC was done which showed Myxochondroid matrix with glandular epithelial cells suggesting pleomorphic adenoma. CT scan head & neck revealed a large mass with nodular areas of calcification within soft tissue with marked narrowing of orophayngeal lumen. Total parotidectomy with preservation of facial nerve was done by the Transcervical Transparotid approach. The histopathological findings suggested the possibility of extensive endochondral ossification in pleomorphic adenoma. Preservation of facial nerve functions is a key to successful parotid surgery. ª 2014 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
1. Introduction About 70% of all salivary gland tumors arise in the parotid gland, and approximately 85% are benign. Pleomorphic adenoma (PA) is the most common benign salivary gland * Corresponding author. Address: Department of ENT & Head Neck Surgery, J.L.N. Hospital & Research Centre, Sector 9, Bhilai, Dist. Durg, Chhattisgarh 490009, India. Tel.: +91 9407983605; fax: +91 0788 2227814. E-mail address: [email protected] (A.A. Jaiswal). Peer review under responsibility of Egyptian Society of Ear, Nose, Throat and Allied Sciences.
Production and hosting by Elsevier
tumor that exhibits a wide cytomorphologic and architectural diversity. It is also known as ‘‘Mixed tumor, salivary gland type’’. The annual incidence is approximately 2–3.5 cases per 100,000 population. This paper describes a case of a huge pleomorphic adenoma arising in the parotid gland with extensive bone formation and treated by total parotidectomy with facial nerve preservation. 2. Case profile A 22 year old male patient presented to OPD of the Department of ENT & Head Neck Surgery, J.L.N. Hospital &Research Centre, Bhilai, with gradually progressive swelling below the left ear since 3 years and difficulty in swallowing since 3 months. On examination, diffuse swelling was seen over the left parotid region extending to the upper part of the neck,
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.2013.12.005
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
2 the skin over the swelling was stretched with no visible pulsations. On palpation it was non tender, hard in consistency, the skin over the swelling was free. On intraoral examination, a smooth bulge was seen on the soft palate & lateral pharyngeal wall. There were no pathologic lymph nodes in the neck. FNAC was done which showed Myxochondroid matrix with glandular epithelial cells suggesting pleomorphic adenoma (Fig. 1). Taking into consideration its consistency & extent a contrast enhanced CT scan head & neck was done which showed a large mass seen at the angle of the mandible occupying the left parapharyngeal space with large nodular areas of calcification within soft tissue with marked narrowing of oropharyngeal lumen (Fig. 2). MRI revealed a large mass of heterogenous texture with multiple soft tissue densities & hypo intense areas with narrowing of oropharyngeal lumen (Fig. 3). Total parotidectomy with preservation of facial nerve was done by the Trancervical Transparotid approach. Excised tumor of size 9 · 8 cm & 400 g by weight was sent for HPE. Grossly cut section showed extensive bone formation (Fig. 4). Histopathological examination showed benign epithelial component in close proximity to cartilage predominance of cartilaginous matrix with enchondral ossification, trabeculae of bone showed bone marrow like structure (Fig. 5). Immunohistochemistry revealed small cells surrounding bony areas positive for S-100 and CK HMW, suggests myoepithelial cells (Fig. 6). The postoperative course was uneventful & facial nerve functions were normal.
A.A. Jaiswal et al.
Figure 2 MRI scan showing a large mass with obliteration of oropharyngeal lumen.
3. Discussion Pleomorphic adenoma (PA) represents 45–74% of all salivary gland tumors and 65% of them occur in the parotid gland.1–3 PA is the most common in third to sixth decades; the average age at presentation is between 43 and 46 years. PA has a slight female predominance.4,5 PA frequently manifests with focal or partial ossified and calcified degeneration but PA of the
Figure 3 FNAC; Myxochondroid matrix along with epithelial cells (MGG, ·40).
Figure 4 Gross specimen showing extensive bony & cartilaginous areas, hard & gritty to cut. Figure 1 CT scan axial view showing a large mass seen at the angle of mandible with large nodular areas of calcification within soft tissue.
parotid gland with extensive bone formation is a rare entity & very few cases have been mentioned in the literature.6,7
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report
Figure 5 H & E, ·40 shows extensive areas of bone formation within cartilage.
Figure 6 cells).
IHC showing positivity for CK HMW (Myoepithelial
Pleomorphic adenoma usually presents as a slow-growing, painless mass, which may be present for many years. Symptoms and signs depend on the location.8 In the parotid, 90% occur in the superficial lobe and most commonly are seen in the tail of the gland. Pleomorphic adenoma in the deep lobe of the parotid gland may present as an oral retrotonsillar mass or parapharyngeal space tumor; indeed, tumors arising at this site are the source of the most common parapharyngeal space tumors. Patients with minor salivary gland tumors may present with a variety of symptoms, depending on the site of the tumor; such symptoms include dysphagia, dyspnea, hoarseness, difficulty in chewing, and epistaxis. In our case pt. presented with gradually progressive swelling along with difficulty in swallowing. The firmness of pleomorphic adenoma varies with the nature & amount of stromal component. So it ranges from soft in the case of more mucinous tumors to hard in tumors with extensive chondroid or collagenous component. In our case, it was hard in consistency due to extensive bone formation. The diagnosis of salivary gland tumors utilizes both tissue sampling and radiographic studies. Tissue sampling proce-
3
dures include fine needle aspiration (FNA) and core needle biopsy (bigger needle comparing to FNA). Both of these procedures can be done in an outpatient setting. In our case FNAC suggested the diagnosis of pleomorphic adenoma. Diagnostic imaging techniques for salivary gland tumors include ultrasound, computer tomography (CT) and magnetic resonance imaging (MRI). CT is excellent for demonstrating bony invasion. MRI provides superior soft tissue delineation such as perineural invasion when compared to CT only.9 Histopathologically, PA shows a remarkable degree of morphology diversity. The essential components are the capsule, epithelial and myoepithelial cells, and mesenchymal or stromal elements.10 The mesenchymal-like component is mucoid/myxoid, cartilaginous, or hyalinized. Focal or partial ossified and calcified degeneration is occasionally seen in PA, but extensive ossified and calcified degeneration as seen in our case is extremely rare. Shi et al. & Shigeishi et al. have described pleomorphic adenoma with extensive bone formation but a tumor of size 9 · 8 cm & 400 g by weight with such extensive bone formation has not been mentioned in the literature. Akasaka et al. suggested that ossification in benign mixed tumors indicates development from pluripotent stem cells.11 Lee et al. in their case report suggested that the bony matrix appears to be deposited directly by metaplastic myoepithelial cells rather than through enchondral ossification.12 As the outcome of the study of Harrison,13 calcification in PA was found in a lumen and in epithelial cells and consisted of needleshaped crystals that contained calcium and phosphorus and were probably apatite; and small collections of crystals in the lumen, which were often associated with membranous cellular debris, appeared to form larger calcified masses by fusion. In most instances, the diagnosis of pleomorphic adenoma is made through a straightforward microscopic identification. However, immunohistochemistry (IHC) may be supportive and helpful in delineating the different cell types and components, as well as in differentiating pleomorphic adenoma from other tumors.14–16 In our case IHC revealed small cells surrounding bony areas positive for S-100 and CK HMW, suggests myoepithelial cells. Treatment of pleomorphic adenomas is a complete surgical excision with a surrounding margin of normal tissue, i.e., superficial/total parotidectomy with facial nerve preservation, submandibular gland excision or wide local excision for a minor salivary gland. Simple enucleation of these tumors is what is believed to have led to high local recurrence rates in the past and should be avoided. Rupture of the capsule and tumor spillage in the wound are also believed to increase the risk of recurrence, so meticulous dissection is paramount.17–20 In our case a total parotidectomy with preservation of facial nerve was done. 4. Summary Pleomorphic adenoma (PA) is the most common benign salivary gland tumor but extensive bone formation in it is extremely rare. FNAC plays an important role in the diagnosis of pleomorphic adenoma. CT scan is helpful in diagnosis, knowing the extent of tumor & calcification status.
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005
4 Surgical excision i.e., superficial/total parotidectomy with preservation of facial nerve is a primary modality of treatment. HPE & IHC are helpful for confirmation of diagnosis.
5. Conflict of interest None.
References 1. Ellis GL, Auclair PL, eds. Atlas of tumor pathology. Tumours of the salivary glands. Washington, DC: Armed Forces Institute of Pathology; 1995:39–41. 2. Speight PM, Barrett AW. Salivary gland tumours. Oral Dis. 2002;8(5):229–240. 3. Ledesma-Montes C, Garces-Ortiz M. Salivary gland tumours in a Mexican sample. A retrospective study. Med Oral. 2002;7(5):324–330. 4. Eveson JW, Cawson RA. Salivary gland tumours: a review of 2410 cases with particular reference to histological types, site, age and sex distribution. J Pathol. 1985;146:51–58. 5. Waldron CA, el Mofty SK, Gnepp DR. Tumors of the intraoral minor salivary glands: a demographic and histologic study of 426 cases. Oral Surg Oral Med Oral Pathol. 1988;66:323–333. 6. Shi H, Wang P, Wang S, Yu Q. Pleomorphic adenoma with extensive ossified and calcified degeneration: unusual CT findings in one case. AJNR Am J Neuroradiol. 2008;29(4):737–738. 7. Shigeishi H, Hayashi K, Takata T, Kuniyasu H, Ishikawa T, Yasui W. Pleomorphic adenoma of the parotid gland with extensive bone formation. Pathol Int. 2001;51(11):883–886. 8. Spiro RH. Salivary neoplasms: overview of a 35-year experience with 2807 patients. Head Neck Surg. 1986;8(3):177–184.
A.A. Jaiswal et al. 9. Koyuncu M, Sesßen T, Akan H, et al. Comparison of computed tomography and magnetic resonance imaging in the diagnosis of parotid tumors. Otolaryngol Head Neck Surg. 2003;129(6):726–732. 10. Barnes L, Eveson JW, Reichart P, et al., eds. World Health Organization classification of tumours: pathology and genetics of head and neck tumours. Lyon, France: IARC Press; 2005:254–258. 11. Akasaka T, Ondera H, Matsuta M. Cutaneous mixed tumour containing ossification, hair matrix, and sebaceous ductal differentiation. J Dermatol. 1997;24:125–131. 12. Lee KC, Chan JKC, Chong YW. Ossifying pleomorphic adenoma of the maxillary antrum. J Laryngol Otol. 1992;106:50–52. 13. Harrison JD. Ultrastructural observation of calcification in a pleomorphic adenoma of the parotid gland. Ultrastruct Pathol. 1991;152:185–188. 14. Kusafuka K, Yamaguchi A, Kayano T, Takemura T. Immunohistochemical localization of the bone morphogenetic protein-6 in salivary pleomorphic adenomas. Pathol Int. 1999;49(12): 1023–1027. 15. Nishimura T, Furukawa M, Kawahara E, Miwa A. Differential diagnosis of pleomorphic adenoma by immunohistochemical means. J Laryngol Otol. 1991;105(12):1057–1060. 16. Stead RH, Qizilbash AH, Kontozoglou T, Daya AD, Riddell RH. An immunohistochemical study of pleomorphic adenomas of the salivary gland: glial fibrillary acidic protein-like immunoreactivity identifies a major myoepithelial component. Hum Pathol. 1988;19(1):32–40. 17. Ellis GL, Auclair PL, Gnepp DR, eds. Surgical pathology of the salivary glands. Philadelphia: WB Saunders; 1991. 18. Eisele DW, Johns ME. Salivary gland neoplasms. In: Bailey BJ, ed. Head & neck surgery-otolaryngology. Philadelphia: Lippincott Williams & Wilkins; 2001:1279–1297. 19. Seifert G, Miehlke A, Haubrich J, Chilla R, eds. Diseases of the salivary glands. New York: Thieme Inc.; 1986. 20. Califano JC, Eisele DW. Benign salivary gland neoplasms. Otolaryngol Clin North Am. 1999;35(5):861–873.
Please cite this article in press as: Jaiswal AA et al. Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report. Egypt J Ear Nose Throat Allied Sci (2014), http://dx.doi.org/10.1016/j.ejenta.2013.12.005