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IMPORTANCE OF ANATOMICAL LANDMARKS DURING PAROTIDECTOMY: A CASE REPORT OF A HUGE PLEOMORPHIC ADENOMA OF THE PAROTID GLAND

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Pleomorphic adenoma is the predominant histocytopathological variant among parotid gland neoplasms involving more frequently the superficial lobe. It's a benign tumour, and without intervention it can grow to an appreciably large mass causing significant morbidity. Normally, the parotid gland weighs about 15 grams. Identification of the surgical landmarks during parotidectomy is of paramount importance since facial nerve preservation is one of the goals in such surgeries. We report a case of a giant pleomorphic adenoma of the parotid gland and its surgical technique in a 70-year old female with a history of that tumour for more than 35 years. Upon examination, a giant mass on the left side of the face was found with no features of facial nerve involvement. Total parotidectomy was done with facial nerve preservation. Macroscopically, the mass weighed 5.2 kilograms with 35× 40 ×32 centimeters. Functional and aesthetic functions were preserved.
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East and Central Africa Journal of Otolaryngology, Head and Neck Surgery | Vol. 3; 2019
IMPORTANCE OF ANATOMICAL LANDMARKS DURING PAROTIDECTOMY: A CASE
REPORT OF A HUGE PLEOMORPHIC ADENOMA OF THE PAROTID GLAND
Mashamba V1, Saitabau Z2, Nkya A3
1Department of Otorhinolaryngology, Muhimbili National Hospital, P.O. Box 65000, Dar es Salaam, Tanzania
2Department of Surgery, University of Dodoma, College of Health and Allied Sciences, P.O. Box 259, Dodoma, Tanzania
3Department of Otorhinolaryngology, Muhimbili University if Health and Allied Sciences, P.O. Box 65001, Dar es
Salaam, Tanzania
Address for correspondence: Dr Victor Mashamba, Department of Otorhinolaryngology, Muhimbili National Hospital,
P.O. Box 65000, Dar es Salaam, Tanzania. Email: victor_mashamba@yahoo.com
ABSTRACT
Pleomorphic adenoma is the predominant histocytopathological variant among parotid gland neoplasms involving more
frequently the supercial lobe. It’s a benign tumour, and without intervention it can grow to an appreciably large
mass causing signicant morbidity. Normally, the parotid gland weighs about 15 grams. Identication of the surgical
landmarks during parotidectomy is of paramount importance since facial nerve preservation is one of the goals in such
surgeries. We report a case of a giant pleomorphic adenoma of the parotid gland and its surgical technique in a 70-
year old female with a history of that tumour for more than 35 years. Upon examination, a giant mass on the left side
of the face was found with no features of facial nerve involvement. Total parotidectomy was done with facial nerve
preservation. Macroscopically, the mass weighed 5.2 kilograms with 35× 40 ×32 centimeters. Functional and aesthetic
functions were preserved.
Key words: Parotid, Pleomorphic adenoma, Facial nerve landmarks, Muhimbili, Tanzania
CASE REPORT
INTRODUCTION
Pleomorphic adenomas are benign salivary gland
tumours, which affect predominantly the supercial
lobe of the parotid gland. They are described to have
“pleomorphism” due to dual presence of epithelial
and connective tissue components histologically1-3.
Pleomorphic adenomas of the parotid gland present
as painless slow growing masses of varying sizes and
involve the supercial lobe in about 80% of cases4,5. It
may undergo malignant transformation to carcinoma ex
pleomorphic adenoma and may then involve the facial
nerve. The standard surgery done for benign parotid
tumours is parotidectomy with adequate resection of the
margins and care taken to preserve the facial nerve3,6-8.
For giant benign parotid tumours, total parotidectomy
may be warranted. Identication of the facial nerve
landmarks serves an important basis for any successful
parotidectomy. The reliable landmarks to identify the
facial nerve trunk are the tympanomastoid suture line,
the tragal cartilage, branches of occipital artery, styloid
process and the posterior belly of the digastric muscle.
Taking into consideration such set landmarks should
be the goal of any surgeon when doing parotidectomy
regardless of any size of the tumour to be resected.
There are few cases of giant pleomorphic adenomas
of the parotid gland reported and to the best of our
knowledge, this is among the biggest parotid pleomorphic
adenomas ever reported in the available literatures in East
Africa and is the only documented case in Tanzania.
CASE REPORT
A 70-year old female presented to our department
complaining of a painless swelling on the left side of the
face for the past 35 years. The mass had been growing
insidiously in size. No history of fevers, excessive night
sweats, bone pain or rapid increase in size of the mass
was reported, and there was no history of prior head
and/or neck irradiation, chewing tobacco or alcohol
consumption.
Upon examination, she was ill looking and wasted
with stable vital signs. She had a huge mass on the left
side of the face involving the preauricular, infra-auricular
regions and mastoid. It was pedunculated hanging down
to mid-chest but with no airway compromise or difculty
in swallowing (Figure 1). The mass was nodulated and
non-tender, mobile and the overlying skin was tense
with some areas of ulceration. The mass measured 35 ×
40cm in its greatest dimensions. No palpable regional
lymph nodes were noted, and facial nerve was intact.
Computerized tomography scan showed a large left
parotid tumour with areas of calcication and necrosis
with no lymph node involvement (Figure 2).
Fine Needle Aspiration Cytology (FNAC) showed
clusters of spindle shaped cells in a myxoid background,
suggesting a pleomorphic adenoma (Figure 3).
The patient underwent surgery in June 2018. She
consented to the use of her medical records and images
for specic purpose of this case report.
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East and Central Africa Journal of Otolaryngology, Head and Neck Surgery | Vol. 3; 2019
Figure 1: 70-year old female with giant parotid mass
Figure 2: CT scan of giant parotid tumour
Figure 3: FNAC showing clusters of spindle shaped
cells in a myxoid background, suggesting a pleomorphic
adenoma
Surgical technique
The operation was done under general anaesthesia with-
out muscle relaxation so that the facial nerve could be
mechanically stimulated. A lazy-S incision was made
with some modication to remove the ulcerated skin
(Figure 4).
Figure 4: Lazy-S incision being planned with modication
to remove the ulcerated skin
The sternocleidomastoid muscle was rst identied,
and the greater auricular nerve located and divided as it
crossed the lateral surface of the muscle. This allowed the
sternocleidomastoid to be retracted posteriorly (Figure
5). The next structure to identify was the posterior belly
of digastric muscle (Figure 6), which was displaced
medially by the tumour. The muscle was followed
posteriorly up to the mastoid process. The tragal cartilage
was then identied and skeletonized to the cartilage
pointer, which is normally located about 1cm superior
and lateral to where the facial nerve exits the stylomastoid
foramen (Figure 7). The tympanomastoid suture line was
identied by palpation. This, together with the previously
mentioned surgical anatomical landmarks, was used
to nd the trunk of the facial nerve where it exited the
stylomastoid foramen (Figure 8).
The facial nerve was dissected anteriorly and found
to be laterally displaced by the large tumour mass. The
temporal, marginal mandibular and cervical branches
could be preserved, while the midfacial branches had to
be sacriced to permit resection of the tumour (Figure 9).
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East and Central Africa Journal of Otolaryngology, Head and Neck Surgery | Vol. 3; 2019
Figure 5 figure 6 figure 7
D
figure 8 figure 9 figure 10
Figure 11 figure 12 figure 13
Figure 11: Skin closed in layers Figure 12: 14 days postoperative with
resolving facial nerve neuropraxia
Figure 13: Histology conrms
pleomorphic adenoma
Figure 5: Tip of forceps (M)
points to anterior margin of
sternocleidomastoid muscle
Figure 6: Posterior belly of
digastric muscle (D) displaced
medially by the tumour
Figure 7: Forceps showing the
tragal cartilage
Figure 8: Facial nerve running
lateral to the tumour
Figure 9: Forceps identifying the
preserved marginal mandibular
branch of the facial nerve
Figure 10: Encapsulated 5.2kg, 35
x 40 x 32cm tumour completely
removed by total parotidectomy
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East and Central Africa Journal of Otolaryngology, Head and Neck Surgery | Vol. 3; 2019
DISCUSSION
Pleomorphic adenomas of the parotid gland present as
painless slow growing masses of varying sizes. In majority
of cases, the supercial lobe is involved. However, it may
involve the deep lobe and parapharyngeal space4,5,7,8. In
this patient, both the deep and supercial lobes were
affected. This tumour may have originated from the deep
lobe due to lateral displacement of the facial nerve and
retromandibular vein.
Various approaches for a successful parotidectomy with
facial nerve preservation are described and can involve
retrograde or anterograde facial nerve approaches9.
Anterograde dissection was preferred for this particular
case owing to difculties in identifying the terminal
branches due the enormous size of the tumour.
It is always important to identify the key surgical
landmarks of the facial nerve during parotidectomy as
previously described in the dissection steps. By using
these surgical landmarks, we were able to remove
this giant pleomorphic adenoma with success with
preservation of the facial nerve. Finding all the facial
nerve landmarks was however challenging in this case
due to the tumour size, and such cases should not be
attempted by inexperienced surgeons.
Reliable landmarks used to identify the facial nerve
trunk in this particular case were the tympanomastoid
suture line, cartilaginous part of the external auditory
canal, tragal cartilage and the posterior belly of the
digastric muscle (Figure 14). There is no consensus in the
available literature regarding the most reliable facial nerve
pointer, as while some literature report tympanomastoid
suture line to be the most precise landmark for facial
nerve10-12, others report otherwise.
Tympanic ring
Tympanomastoid suture
Stylomastoid foramen
Styloid process
Cartilage
pointer
Mastoid process
Digastric muscle
Figure 14: Schematic surgical landmarks for the
facial nerve trunk (Courtesy: Open Access Atlas of
Otolaryngology, Head and Neck Operative Surgery)
12(https://vula.uct.ac.za/access/content/group/ba5fb1bd-
be95-48e5-81be-586fbaeba29d/Parotidectomy-1.pdf)
CONCLUSIONS
Our case report shows that pleomorphic adenomas can
grow to an enormously massive size (5.2 kilograms)
over a period of more than 35 years. This long duration
may be attributed to several factors such as a patient’s
lack of information, customs and traditions, and fear of
surgery1. Prolonged duration of pleomorphic adenomas
is associated with increased risk of transformation to
carcinoma ex-pleomorphic adenoma. Parotid gland
surgery, regardless of the tumour size, requires a clear
understanding of the surgical anatomy to safely identify
and preserve the facial nerve. In this case we managed to
remove a huge mass weighing about 5.2kg with clinical
identication and preservation of the facial nerve and
other adjacent important structures.
REFERENCES
1. Takahama A, Da Cruz Perez DE, et al. Giant
pleomorphic adenoma of the parotid gland. Med
Oral Patol Oral Cir Bucal. 2008; 13(1):58–60.
2. Dwivedi N, Agarwal A, et al. Histogenesis of
salivary gland neoplasms. Indian J Cancer [Internet].
2013; 50(4):361. Available from: http://www.
indianjcancer.com/text.asp?2013/50/4/361/123629
3. Friedrich RE, Li L, et al. Pleomorphic adenoma
of the salivary glands: Analysis of 94 patients.
Anticancer Res. 2005; 25(3 A):1703–5.
4. Koral K, Sayre J, et al. Recurrent pleomorphic
adenoma of the parotid gland in pediatric and adult
patients: Value of multiple lesions as a diagnostic
indicator. Am J Roentgenol. 2003; 180(4):1171–74.
5. Datarkar AN, Deshpande A. Giant parapharyngeal
space pleomorphic adenoma of the deep lobe of
parotid presenting as obstructive sleep apnoea:
A case report & amp; Review of the diagnostic
and therapeutic approaches. J Maxillofac Oral Surg
[Internet]. 2015; 14(3):532–537. Available from:
http://link.springer.com/10.1007/s12663-014-0690-0
6. Nagaraj H, Raikar RN, et al. The world’s biggest
benign parotid tumour “pleomorphic adenoma”:
a rare case report. IOSR J Dent Med Sci Ver II
[Internet]. 2014; 13(2):2279–861. Available from:
www.iosrjournals.org
7. Jain S, Hasan S, Vyas N, et.al. Pleomorphic
adenoma of the parotid gland : report of a case with
review of literature. Ethiop J Health Sci [Internet].
2015; 25(2):189–194. Available from: https://www.
ncbi.nlm.nih.gov/pmc/articles/PMC4478272/pdf/
EJHS2502-0189.pdf
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East and Central Africa Journal of Otolaryngology, Head and Neck Surgery | Vol. 3; 2019
8. Shigeishi H, Ohta K, et al. Clinicopathological
analysis of salivary gland carcinomas and literature
review. Mol Clin Oncol [Internet]. 2015; 3(1):202–
206. Available from:https://www.spandidos
publications.com/
9. O’Regan B, Bharadwaj G, et.al. Techniques for
dissection of the facial nerve in benign parotid surgery:
a cross specialty survey of oral and maxillofacial and
ear nose and throat surgeons in the UK. Br J Oral
Maxillofac Surg. 2008; 46(7):564–566.
10. De RuJ. Alexander et.al. Landmarks for parotid gland
surgery. J Laryngol Otol. 2001; 115: 122–125.
11. Tahwinder U, Waseem J, et al. The stylomastoid artery
as an anatomical landmark to the facial nerve during
parotid surgery. World J Surg Oncol, 2009; 7:71.
12. Fagan JJ. Parotidectomy. Open Access Atlas
of Otolaryngology, Head and Neck Operative
Surgery(https://vula.uct.ac.za/access/content/
group/ba5fb1bd-be95-48e5-81be-586fbaeba29d/
Parotidectomy-1.pdf).
ResearchGate has not been able to resolve any citations for this publication.
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Pleomorphic adenoma is a benign epithelial tumor of adenoid structure preferentially arising from the parotid gland. It was shown that complete tumor excision is a curative measure and recurrence is likely in incompletely excised tumors. The aim of this study was to analyse the outcome of patients with pleomorphic adenoma from salivary glands in order to evaluate the surgical strategy of a single institution. The files of 94 patients were evaluated. Special attention was given to the development of malignancy in pleomorphic adenoma. The pleomorphic adenoma preferentially originated in the parotid gland (n=73; right 48, left: 25), and rarely in other glands. The tumor occurred more often in females than in males (45:28, parotid). In 73 patients a slowly growing swelling of the parotid was first noted, which was located at different sites within the gland. At least one recurrence was noted in 18 patients, the majority of them aged 50 to 70 years (n=12). Malignant transformation to carcinoma was found in 8.5%. Pleomorphic adenoma from salivary glands is a benign tumor. However, in a noteworthy number of patients, inside the benign tumor a phenotype develops with distinct properties of malignancy. Surgery with safety margins is the therapy of choice. Multinodular tumors are prone to recurrent disease.
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Pleomorphic adenomas are benign salivary gland tumors, which predominantly affect the superficial lobe of the parotid gland. The "pleomorphic" nature of the tumor can be explained on the basis of its epithelial and connective tissue origin. The tumor has a female predilection between 30-50 years of age. Slowly progressing asymptomatic swelling is the usual presentation of the tumor. Surgical excision of the tumor mass forms the mainstay of treatment, with utmost care taken to preserve the facial nerve. This case report aims to throw light on an interesting case of pleomorphic adenoma of the parotid gland in a 50 years old female patient. The patient presented with a slowly progressing asymptomatic swelling on the left side of the face. There is also a special emphasis to a detailed review of literature. Salivary gland neoplasms can occur at any site where salivary tissue is present. Pleomorphic adenoma is the commonest salivary gland tumor characterized by diverse histomorphological features. Early diagnosis and treatment plan entails thorough history taking, clinical examination, coupled with radiographic and histopathological findings.
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Many surgical landmarks have been suggested to help the surgeon identify the facial nerve when performing parotid gland surgery. There is no conclusive evidence that any one landmark is better than the rest. In this study distances from the most frequently used surgical landmarks to the main trunk of the facial nerve were measured in 30 halves of cadaver heads. Two ENT surgeons assessed the best landmark in each case. The tympanomastoid suture was nearest to the main trunk and was therefore considered the most reliable landmark. Its average distance to the main trunk of the facial nerve was 2.7 mm. This result was consistent with the subjective best score given by two ENT surgeons.
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Recurrent pleomorphic adenoma of the parotid gland is a significant problem. Rates have been as high as 40% in some series of patients who have undergone surgery for the primary lesion. In the imaging literature, anecdotal case reports show multiple lesions in recurrent pleomorphic adenoma. Our aim was to analyze the imaging of a series of patients to determine the reliability of multiple lesions as a tool in diagnosing recurrent disease. Medical records of the patients with recurrent pleomorphic adenoma of the parotid gland referred to our institution were retrospectively reviewed. Before the second surgery, MR imaging had been performed in 15 patients. We retrospectively reevaluated and scored the MR imaging studies with particular attention paid to the location and number of the lesions and the remaining parotid gland tissue. On the basis of imaging findings, eight patients underwent enucleation, superficial parotidectomy had been performed in four patients, and three patients underwent total parotidectomy. For our group, the lesions were multiple in 73.3% of patients. To our knowledge, we present the first large series of imaging studies in recurrent pleomorphic adenoma of the parotid gland. Our findings show that recurrent pleomorphic adenomas are most likely to be multiple. Such multiplicity of lesions is a reliable diagnostic indicator of recurrent disease.
Giant pleomorphic adenoma of the parotid gland
  • A Takahama
  • Cruz Da
  • D E Perez
Takahama A, Da Cruz Perez DE, et al. Giant pleomorphic adenoma of the parotid gland. Med Oral Patol Oral Cir Bucal. 2008; 13(1):58-60.
Giant parapharyngeal space pleomorphic adenoma of the deep lobe of parotid presenting as obstructive sleep apnoea: A case report & amp
  • A N Datarkar
  • A Deshpande
Datarkar AN, Deshpande A. Giant parapharyngeal space pleomorphic adenoma of the deep lobe of parotid presenting as obstructive sleep apnoea: A case report & amp;