Egyptian Journal of Ear, Nose, Throat and Allied Sciences (2014) 15, 139–142

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

* 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: ash1978jaiswal@gmail.com (A.A. Jaiswal).

Peer review under responsibility of Egyptian Society of Ear, Nose,

Throat and Allied Sciences.

Production and hosting by Elsevier

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

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

Available online 11 January 2014

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 neo-

plasms. 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 epi-

thelial cells suggesting pleomorphic adenoma. CT scan head & neck revealed a large mass with nod-

ular 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 ossi-

fication in pleomorphic adenoma. Preservation of facial nerve functions is a key to successful par-

otid 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 parotidgland, and approximately 85% are benign. Pleomorphic

adenoma (PA) is the most common benign salivary gland

tumor that exhibits a wide cytomorphologic and architecturaldiversity. It is also known as ‘‘Mixed tumor, salivary glandtype’’. The annual incidence is approximately 2–3.5 cases per100,000 population. This paper describes a case of a huge pleo-

morphic adenoma arising in the parotid gland with extensivebone formation and treated by total parotidectomy with facialnerve preservation.

2. Case profile

A 22 year old male patient presented to OPD of the Depart-

ment of ENT & Head Neck Surgery, J.L.N. Hospital &Re-search Centre, Bhilai, with gradually progressive swellingbelow the left ear since 3 years and difficulty in swallowing

since 3 months. On examination, diffuse swelling was seen overthe left parotid region extending to the upper part of the neck,

Figure 2 MRI scan showing a large mass with obliteration of

oropharyngeal lumen.

140 A.A. Jaiswal et al.

the skin over the swelling was stretched with no visible pulsa-tions. On palpation it was non tender, hard in consistency, theskin over the swelling was free. On intraoral examination, a

smooth bulge was seen on the soft palate & lateral pharyngealwall. 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 acontrast enhanced CT scan head & neck was done which

showed a large mass seen at the angle of the mandible occupy-ing the left parapharyngeal space with large nodular areas ofcalcification within soft tissue with marked narrowing oforopharyngeal lumen (Fig. 2). MRI revealed a large mass of

heterogenous texture with multiple soft tissue densities & hypointense areas with narrowing of oropharyngeal lumen (Fig. 3).Total parotidectomy with preservation of facial nerve was

done by the Trancervical Transparotid approach. Excisedtumor 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 epithe-lial component in close proximity to cartilage predominance ofcartilaginous matrix with enchondral ossification, trabeculae

of bone showed bone marrow like structure (Fig. 5). Immuno-histochemistry revealed small cells surrounding bony areas po-sitive for S-100 and CK HMW, suggests myoepithelial cells(Fig. 6). The postoperative course was uneventful & facial

nerve functions were normal.

3. Discussion

Pleomorphic adenoma (PA) represents 45–74% of all salivarygland 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 slightfemale predominance.4,5 PA frequently manifests with focal orpartial ossified and calcified degeneration but PA of the

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.

Figure 3 FNAC; Myxochondroid matrix along with epithelial

cells (MGG, ·40).

Figure 4 Gross specimen showing extensive bony & cartilagi-

nous areas, hard & gritty to cut.

parotid gland with extensive bone formation is a rare entity& very few cases have been mentioned in the literature.6,7

Figure 5 H & E, ·40 shows extensive areas of bone formation

within cartilage.

Figure 6 IHC showing positivity for CK HMW (Myoepithelial

cells).

Pleomorphic adenoma of parotid gland with extensive bone formation – A rare case report 141

Pleomorphic adenoma usually presents as a slow-growing,

painless mass, which may be present for many years. Symp-toms 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 lobeof the parotid gland may present as an oral retrotonsillar massor parapharyngeal space tumor; indeed, tumors arising at this

site are the source of the most common parapharyngeal spacetumors. Patients with minor salivary gland tumors may presentwith a variety of symptoms, depending on the site of the tu-mor; such symptoms include dysphagia, dyspnea, hoarseness,

difficulty in chewing, and epistaxis. In our case pt. presentedwith gradually progressive swelling along with difficulty inswallowing.

The firmness of pleomorphic adenoma varies with the nat-ure & amount of stromal component. So it ranges from soft inthe 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 tissuesampling and radiographic studies. Tissue sampling proce-

dures include fine needle aspiration (FNA) and core needlebiopsy (bigger needle comparing to FNA). Both of theseprocedures 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 demonstratingbony invasion. MRI provides superior soft tissue delineationsuch as perineural invasion when compared to CT only.9

Histopathologically, PA shows a remarkable degree ofmorphology diversity. The essential components are the cap-sule, epithelial and myoepithelial cells, and mesenchymal orstromal elements.10 The mesenchymal-like component is mu-

coid/myxoid, cartilaginous, or hyalinized. Focal or partialossified 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 de-scribed pleomorphic adenoma with extensive bone formationbut a tumor of size 9 · 8 cm & 400 g by weight with such exten-

sive bone formation has not been mentioned in the literature.Akasaka et al. suggested that ossification in benign mixed tu-mors indicates development from pluripotent stem cells.11

Lee et al. in their case report suggested that the bony matrixappears to be deposited directly by metaplastic myoepithelialcells rather than through enchondral ossification.12 As the out-come of the study of Harrison,13 calcification in PA was found

in a lumen and in epithelial cells and consisted of needle-shaped crystals that contained calcium and phosphorus andwere probably apatite; and small collections of crystals in the

lumen, which were often associated with membranous cellulardebris, 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 supportiveand helpful in delineating the different cell types and compo-

nents, as well as in differentiating pleomorphic adenoma fromother tumors.14–16 In our case IHC revealed small cells sur-rounding bony areas positive for S-100 and CK HMW, sug-gests myoepithelial cells.

Treatment of pleomorphic adenomas is a complete surgicalexcision 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 min-or salivary gland. Simple enucleation of these tumors is what isbelieved to have led to high local recurrence rates in the past

and should be avoided. Rupture of the capsule and tumorspillage in the wound are also believed to increase the risk ofrecurrence, so meticulous dissection is paramount.17–20 Inour case a total parotidectomy with preservation of facial

nerve was done.

4. Summary

� Pleomorphic adenoma (PA) is the most common benignsalivary gland tumor but extensive bone formation in it isextremely rare.� FNAC plays an important role in the diagnosis of pleomor-

phic adenoma.� CT scan is helpful in diagnosis, knowing the extent oftumor & calcification status.

142 A.A. Jaiswal et al.

� Surgical excision i.e., superficial/total parotidectomy with

preservationof facial nerve is a primarymodality 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.

9. Koyuncu M, Ses�en 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 differ-

entiation. 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. Immuno-

histochemical 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.