PLEOMORPHIC ADENOMA OF THE DEEP PAROTID GLAND INTRODUCTION Most salivary gland tumors are benign and most common site is parotid. 80% of parotid gland tumors are benign of which 80% are pleomorphic adenomas and 80% arise from the superficial lobe of parotid. •
Over 84% of pleomorphic adenoma occurs in parotid gland, 8% occur in the submandibular gland and 6.4% occur in the minor salivary gland.
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Pleomorphic adenomas are typically seen in the middle aged women and present as painless, slowly growing mass. Transformation into malignant is seen in 2 to 5% of cases and is usually associated with tumors that have been present for 10 to 15 years.
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When they arise from the deep lobe of parotid they can appear entirely extraparotid, seen in the pharyngeal space.
Surgical excision is curative, however tumor is poorly encapsulated (despite imaging suggesting otherwise) there is significant rate of recurrence.
CASE REPORT •
A young 18 years old female presented in opd(IIMCT RAILWAY HOSPITAL RAWALPINDI)with complaint of right sided swelling below ear over the face near the angle of the jaw ON 12-11-12
Swelling was present for the last 8 months and initially was small in size about pea size. Swelling was not associated with pain, fever, redness, or any discharge and no hindrance in swallowing or chewing. •
FNAC of the swelling done at ( PAROTID GLAND.
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On examination patient vitals were stable.examination of the swelling of parotid gland showed that it was about peer shaped 6.4.3 cm in dimensions , smooth edges which are diffused with surrounding tissues, firm in consistency , overlying skin is pinchable , parotid duct inside the mouth opening was normal , papilla normal , FACIAL NERVE intact , no mouth deviation or eye sign.
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Patient was prepared for operation and operated on 15-11-12 as excision of the right deep parotid gland tumor by periauricular submandibular incision. Findings were encapsulated lump of deep lobe of right parotid gland. Facial nerve identified and saved from injury, and drain was put into wound. Drain out put was 80 to 100 ml for the first 2 days and then decreased to 20 to 30 ml in the next 2 days; drain was removed on 4th post op day.
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There were slight deviation of right side of mouth and dryness of right eye, patient being advised of polyfax eye ointment and neuroparax(multivitamins)
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Specimen sent for histopathology and report is awaited, patient discharged on 21-11-12.
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) showed PLEOMORPHIC ADENOMA OF THE
DISCUSSION The parotid gland is situated in the musculoskeletal recess formed by portions of the temporal bone, atlas and mandible, and their related muscles. The gland has a superficial and deep lobe, between which runs the extratemporal portion of the facial nerve. The deep lobe is in contact with the parapharyngeal space. The deep cervical fascia surrounds the parotid gland. This fascia has an anteroinferior portion that becomes the stylomandibular ligament, separating the parotid gland from the submandibular gland. The facial nerve exits the stylomastoid foramen just posterior to the base of the styloid, gives off small branches to the postauricular and posterior belly of the digastric muscles, and then turns anterolaterally. [1] Pleomorphic adenoma is the most common parotid gland tumor accounting for 60-65% of all the salivary gland tumors. [2] It is rarely seen in young children with frequency rates of around 1.5% [3] of all the salivary gland tumors, therefore this case is one of the uncommon cases. Salivary gland pathologies in children are mostly inflammatory [3] but malignant pathologies can also be seen in young ones although pleomorphic adenoma affects middle aged population. Eveson and Cawson [2] found pleomorphic adenoma to affect the population from 13-87 years with an average of 46years and slightly female propensity. Bianchi and Cudmore, the only UK survey found in a literature search, quote a frequency of 1.28% of all salivary gland tumors. [4] This was over a 23-year period and studying a total of 937 patients. The most common lesion was the pleomorphic adenoma, 10 out of 12 tumors (83%), and 90% of these were found in the parotid gland. Callender et al. [5] saw 29 patients between 3 and 16 years with salivary neoplasms. Eight of these were pleomorphic adenomas and were seen in patients between 10 and 16 years with an equal sex distribution. Six of these were in the parotid gland. Kessler and Handler [6] saw 15 salivary gland lesions in children in a 9-year period in Philadelphia. The 7 benign tumors seen were all pleomorphic adenomas with the 8 malignant lesions. Of the pleomorphic adenomas 6 were found in the parotid gland out of a total of 12 parotid tumors. Hence while treating young patients with swelling over the parotid gland one most take into consideration the malignant aspect of the swelling, although uncommon but pleomorphic adenoma can present in early ages. Debets, J. M. H. and Munting, J. D. K. (1992),[7] treated 150 patients surgically by superficial or total parotidectomy of parotid tumors over the period of 19 years, of which 92
patients had pleomorphic adenoma and after the follow up of mean 7.7years there was no recurrence. However, permanent facial paralysis occurred in 4 patients. Maynard, J. D. (1988) [8] performed a series of 336 parotidectomies for benign disease of which 130 were wide excision for pleomorphic adenomas and followed up for 20 years. Recurrence occurred in only one patient and 20 patients experienced some degree of facial nerve weakness postoperatively there was only one case of permanent weakness. Stevens, K. L. and Hobsley, M. (1982), [9] reviewed 100patients undergoing parotidectomy, 72 patients had parotidectomy for primary pleomorphic adenoma while 28 had recurrent adenoma. After a follow-up of 1–15 years (median 4 years), there were no recurrences in the primary group but 5 recurrences among the secondary cases. Permanent facial nerve damage was not seen in the primary group, but 11 patients undergoing secondary parotidectomy were left with some permanent facial weakness Hence we can conclude that the pleomorphic adenoma is also the most common tumor among the salivary gland tumors of young age and treatment of choice for pleomorphic adenoma is surgical parotidectomy, but it can lead to some facial nerve weakness postoperatively even though care is taken to save facial nerve. But this weakness is mostly temporary and can lead to complete recovery with time.
REFERENCES: 1. http://emedicine.medscape.com/article/194357-overview#a04 2. Eveson J W, Cawson R A. Salivary gland tumours: a review of 2410 cases with particular reference to histological types, sites, age, sex, and sex distribution. J Pathology 1985; 146: 51–58. 3. Kroll's S G, Trodahl N J, Boyers RC. Salivary gland lesions in children: a survey of 430 cases. Cancer 1972; 30: 459-469 4. Bianchi A, Cudmore R E. Salivary gland tumours in children. J Paediatr Surg 1978; 13: 519–521. 5. Callender D L, Frankenhaler R, Luna M, Sook Lee S, Goepfert H. Salivary neoplasms in children. Arch Otolaryngol Head Neck Surg 1992; 118: 472–476. 6. Kessler A, Handler S D. Salivary gland neoplasms in children; a 10 year survey at The Children's Hospital of Philadelphia. Int J Paediatr Oto Rhino Laryngo 1994; 29: 195–202.
7. Debets, J. M. H. and Munting, J. D. K. (1992), Parotidectomy for parotid tumours: 19-year experience from the Netherlands. Br J Surg, 79: 1159–1161. doi: 10.1002/bjs.1800791116 8. Maynard, J. D. (1988), Management of pleomorphic adenoma of the parotid. Br J Surg, 75: 305–308. doi: 10.1002/bjs.1800750403 9. Stevens, K. L. and Hobsley, M. (1982), the treatment of pleomorphic adenomas by formal parotidectomy. Br J Surg, 69: 1–3. doi: 10.1002/bjs.1800690102
