The parotid tumours-benign and malignant: our experience

INTRODUCTION

The chances of a tumor being benign are more in major salivary glands (80% of parotid and 50-60% of submandibular) while less in minor salivary glands (25%).^1,2 The parotid gland is the most commonly involved salivary gland with an incidence of 70% followed by the submandibular gland and other minor salivary gland tumors.² The major salivary glands are a common source of benign pathology, both inflammatory and neoplastic.^2,3 Salivary gland tumors comprise 0.3% of all malignancies and 2-6.5% of the head-and-neck tumor. German surgeon Lorenz Heister is credited for the description of the first parotidectomy in 1765, which he mentioned in his book "A General System of Three Parts". All age groups are affected with the peak incidence in the 50-60 years age. There is a female preponderance with exception of Warthin's tumors, which are more common in males.

The study aims to analyze parotid tumors retrospectively with the following objectives: correlation of cytological and histopathological findings of parotid gland tumors; preservation of the posterior branch of the greater auricular nerve during parotid surgery; and preservation of facial nerve and its branches during parotid surgery.

CASE SERIES

It was a prospective observational study involving 21 patients who presented with parotid region swelling in the outpatient department of ENT. After obtaining informed and written consent from all the patients they underwent a protocol of detailed history, clinical, radiological, cytological (FNAC), and histopathological (HPE) evaluation.

A total of 21 patients were involved in our study.

In the present study, the maximum numbers of cases were in the age group of 21-40 years (57%), followed by 24% in 41-60 years (Table 1).

Around 57% of female patients were noted in our study (Table 2). So more incidences were noted in females than males.

Around 52% of patients had swelling on the right side, and 48% on the left side. There was no any side predilection for parotid tumors (Table 3 and Figure 1).

1st arrow-superficial parotid lobe, 2nd arrow- deep lobe of parotid

FNAC was done in all cases which were suggestive of benign tumors. Pleomorphic adenoma (15 cases-71%) was the most frequent benign tumor, followed by Warthin's tumor in 14% of cases and benign cystic lesion in 10% of cases (Table 4).

A postoperative parotid swelling specimen was sent for histopathological examination. Out of 21 cases, 20% non-neoplastic lesion was found, 68% benign neoplastic lesion and 15% malignant neoplastic lesion were reported (Table 5).

Among 11 cases pre-operative FNAC and post-operative histopathology were the same and 10 cases reports different.

Preservation of the posterior branch of GAN during parotid surgery

GAN preservation was determined by its objective feasibility and by the surgeon's preference; the risk of parotidectomy was explained to all patients, including those related to the sacrifice of GAN or one of its branches. We preserved the posterior branch of GAN in 19/21 (90%) patients. We did not take into account the preservation of the anterior branch of GAN because generally during skin flap elevation it is necessary to divide it. In 2/21 (10%) patients GAN was sacrificed (Figure 2).

Preservation of facial nerve and its branches

We had to identify the facial nerve by a divergent technique by following landmarks (Figure 3).

Digastric muscle- the nerve is immediately superior to the posterior belly of the digastric. Tragal pointer- the facial nerve trunk is commonly found 1 cm inferior and 1 cm deep to the tragal pointer.

Careful blunt dissection immediately on the epineurium of the nerve with slow advancement and spreading action had been done. The same had been followed till identify all branches.

Anatomical integrity of the facial nerve with its all branches had been maintained in 19 (90%) cases, in 17 cases of superficial parotidectomy and 2 cases of total parotidectomy. In 1 case upper buccal branch could not be saved and in 1 case marginal branch was sacrificed.

In the postoperative period in which we preserved anatomical integrity, we had seen 3 cases of grade III (House Brackmann) facial palsy and 2 cases of grade IV (House Brackmann) facial palsy, which was recovered in 4 cases in 1 month and 1 case in 3 months with injectable followed by oral steroid and facial physiotherapy.

Arrows 1st facial nerve main trunk, 2nd retromandibular vein.

DISCUSSION

In the present study, the sensitivity of FNAC is 100%, specificity is 75%, [positive predictive value is 94.45% and negative predictive value is 100%] whereas accuracy is 95.24%, compared with other authors.

Among benign tumors, pleomorphic adenoma was the most common and which is consistent with the literature. Being benign it is easily removable with a good prognosis. In our study, we found that FNAC and HPE were the same in 11 cases.

The result of FNAC varies according to the examiner`s experience and diagnostic skill, a good understanding between an otolaryngologist and pathologist results in the outcome.⁷

In our study, we preserved the posterior branch of GAN in 19 (90%) cases.

In Christensen and Jacobsen`s opinion, the posterior branch could be preserved in 71% of patients.

Surgical excision is the mainstay of treatment either benign or malignant lesions of the parotid gland. According to national multidisciplinary guidelines published in 2016 from the United Kingdom, all benign tumors must undergo complete excision making every effort to preserve facial nerve.^8,9

Anatomical integrity of the facial nerve with its all branches had been maintained in 19 (90%) cases in 17 cases of superficial parotidectomy and 2 cases of total parotidectomy.

In 1 case upper buccal branch could not be saved and in 1 case marginal branch was sacrificed.

In the postoperative period in which we preserved anatomical integrity, we had seen 3 cases of grade III (House Brackmann) facial palsy and 2 cases of grade IV (House Brackmann) facial palsy which was recovered in 4 cases in 1 month and 1 case in 3 months.

In this study, 19 (90%) cases show preservation of the Facial nerve with 2 cases in which involvement of one branch of the facial nerve was seen.

The most significant complication is facial nerve dysfunction which can appear as paralysis (complete loss of function) or paresis (partial loss).^10,11

In the literature, the percentage of facial postoperative paralysis varies from 10% to 70% for transient involvement, and from 0 to 19% for definitive involvement.^12-18

CONCLUSION

It seems that maximal GAN preservation when feasible may offer a better quality of life after surgery to the patient. Despite the high incidence of postoperative facial paresis, the prognosis is good due to preserved anatomical integrity.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

1. 1. Watkinson J, Clarke R. Scott Brown’s Otolorhinolaryngology. Head and Neck Surgery. 8th edition. Volume 3. CRC Press. 2018;9:115-30.
2. 2. Watkinson J, Clarke R. Scott Brown’s Otolorhinolaryngology, Head and Neck Surgery. Volume 2: Paediatrics, The Ear, and Skull Base Surgery. 8th edition. Volume 3. CRC Press. 2018;10:131-50.
3. 3. Watkinson J, Gilbert RW. Stell & Maran’s Textbook of head and neck surgery and oncology. 5th Edition. Hodder Arnold. 2012;37:714-28.
4. 4. Cajulis RS, Gokaslan ST, Yu GH, Frias-Hidvegi D. Fine needle aspiration biopsyof salivary glands. A five year experience with emphasis on diagnostic pitfall. Acta Cytol. 1997;41(5):1412-20.
5. 5. Boccato P, Altavilla G, Blandamura S. Fine needle aspiration biopsy of salivary gland lesions. Are appraisal of pitfall & problems. Acta Cytol. 1998;42(4):888-98.
6. 6. Stewart CJ, Mac Kenzie K, Mc Garry GW, Mowat A. Fine needle aspiration cytology of salivary gland: A review of 341 cases. Diagn Cytopathol. 2018;22(3):139-46.
7. 7. Naz S, Hashmi AA, Khurshid A, Faridi N, Edhi MM, Kamal A, et al. Diagnostic roleof fine needle aspiration cytology (FNAC) in the evaluation of salivary gland swelling: an institutional experience. BMC Res Notes. 2015;8:101.
8. 8. Maahs GS, Oppermann Pde O, Maahs LG, Machado Filho G, Ronchi AD. Parotid gland tumors: a retrospective study of 154 patients. Braz J Otorhinolaryngol. 2015;81(3):301-6.
9. 9. Guerra G, Testa D, Montagnani S, Tafuri D, Salzano FA, Rocca A, et al. Surgical management of pleomorphic adenoma of parotid gland in elderly patients: role of morphological features. Int J Surg. 2014;12(2):S12-6.
10. 10. Banerjee P, Sikdar B, Das G, Das A, Ghosh A. Parotidectomy, complications and management: our experience. Int J Otorhinolaryngology Head Neck Surg. 2020;6:1617-22.
11. 11. Maithani T, Pandey AK, Agrahari AK. An Overview of Parotidectomy for Benign Parotid Lesions with Special Reference to Perioperative Techniques to Avoid Complications: Our Experience. Indian J Otolaryngology Head Neck Surg. 2019;71(Suppl 1):258-64.
12. 12. Guntinas-Lichius O, Kick C, Klussmann JP, Jungehuelsing M, Stennert E. Pleomorphicadenoma of the parotid gland: a 13-year experience of consequent management by lateral or total parotidectomy. Eur Arch Otorhinolaryngology. 2004;261(3):143-6.
13. 13. Gaillard C, Perie S, Susini B, St Guily JL. Facial nerve dysfunction after parotidectomy: the role of local factors. Laryngoscope. 2005;115:287-91.
14. 14. Gonzalez-Cardero E, Infente-Cassio P, Cayuela A, Acosta-Feria M, Gutierrez-Perez JL. Facial disability index (FDI): adaptation to Spanish, reliability & validity. Med Oral Pathol Oral Cir Bucal. 2012;17:e1006-12.
15. 15. Marchese-Ragona R, DeFilippis C, Marioni G, Staffieri A. Treatment of complications of parotid gland surgery. Acta Otorhinolaryngology Ital. 2005;25:174-8.
16. 16. Yuan X, Gao Z, Jiang H, Yang H, Lv W, Wang Z, et al. Predictors of facial palsy aftersurgery for benign parotid disease: multivariate analysis of 626 operations. Head Neck. 2009;31:1588-92.
17. 17. Maddox PT, Paydarfar JA, Davies L. Parotidectomy: a 17-year institutional experience at a rural academic medical center. Ann OtoRhino Laryngology. 2012;121:100-3.
18. 18. Ruohoalho J, Makitie AA, Aro K, Atula T, Haapaniemi A, Keski-Santti H, et al. Complications after surgery for benign parotid gland neoplasms: A prospective cohort study. Head Neck. 2017;39:170-6.