|Year : 2020 | Volume
| Issue : 2 | Page : 186-188
A rare case of parotid gland lipoma arising from the superficial lobe of the parotid gland
Danaveni Raju, Goud G Srikanth, Arutla Rashmitha, Shivaranjani Kistareddy
Department of Oral Medicine and Radiology, SVS Institute of Dental Sciences, Mahabubnagar, Telangana, India
|Date of Submission||28-Jan-2020|
|Date of Decision||05-Mar-2020|
|Date of Acceptance||25-Apr-2020|
|Date of Web Publication||27-Jun-2020|
Dr. Arutla Rashmitha
SVS Institute of Dental Sciences, Appannapally, Mahabubnagar, Telangana - 509 002
Source of Support: None, Conflict of Interest: None
| Abstract|| |
A lipoma is a fatty tissue tumor presenting as a painless slowly growing mass that arise in any location where fat is normally present. It is a soft tissue tumor of the mesenchymal origin, quite uncommon in the head and neck region, only occurring in about 15% of all cases. Posterior cervical triangle and forehead are usually the sites of occurrence, with very few cases occurring in oral cavity, pharynx, larynx, parotid and parapharyngeal space. Lipoma affecting the parotid gland is extremely rare, consisting of only 0.6–4.4% of all parotid tumors. Considering the rarity, here we report a case of 55-year-old male who presented with swelling in the left parotid region.
Keywords: Benign, lipoma, parotid gland
|How to cite this article:|
Raju D, Srikanth GG, Rashmitha A, Kistareddy S. A rare case of parotid gland lipoma arising from the superficial lobe of the parotid gland. J Indian Acad Oral Med Radiol 2020;32:186-8
|How to cite this URL:|
Raju D, Srikanth GG, Rashmitha A, Kistareddy S. A rare case of parotid gland lipoma arising from the superficial lobe of the parotid gland. J Indian Acad Oral Med Radiol [serial online] 2020 [cited 2020 Jul 11];32:186-8. Available from: http://www.jiaomr.in/text.asp?2020/32/2/186/288126
| Introduction|| |
Lipoma was first reported by Roux in 1848. Lipoma is a benign soft tissue tumor and it can occur in any parts of the body and it can be solitary or multiple. Lipoma in the light of literature, accounts to about 0.6–4.4% of all parotid tumors. Clinically they present as painless, mobile, and well-differentiated mass in the parotid region. Lipoma is most commonly reported in 5th–6th decade of life with male predilection (male: females ratio of 10:1).
| Case Report|| |
A 55-year-old male patient presented with a slow-growing, huge, painless mass in left preauricular region for the past 4 years, which was initially small in size and gradually attained the present size [Figure 1]. Clinical examination showed a soft, non-tender, mobile mass which is 6 × 4 cm in size approximately [Figure 2]. The overlying skin was normal without any sign of adhesion and slippery sign was not present. The facial nerve function was unremarkable and the surface of the swelling appeared to be smooth. Based on the history given by the patient and clinical examination a provisional diagnosis of benign salivary gland tumor of the left parotid gland was given for which differential diagnosis of pleomorphic adenoma, Warthin's tumor were given.
|Figure 1: (a and b) Extraoral photograph of the patient showing swelling on the left side of the face|
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|Figure 2: (a) Axial and (b) Coronal CT section showing large, well defined hypodense lesion (HU values -4 to -120 HU) showing fat density and few areas of isointensity noted in the left parotid gland|
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The patient was subjected to ultrasonography of the left parotid region showed a well-defined, heterogeneously hyperechoic lesion suggestive of lipoma. Fine needle aspiration cytology (FNAC) was performed and it revealed clusters and group of mature adipocytes seen in hemorrhagic background and these features suggestive of lipoma. Computed tomographic imaging revealed a large well-defined hypodense lesion (HU values -4 to -120 HU) showing fat density and few areas of isointensity noted in left parotid gland measuring approximately (AP: Tr: CC -5 × 4.9 × 5.8 cm) with speck of ring calcifications (HU Values 4 to 200 HU) noted in the medial aspect, causing mass effect on surrounding parotid tissue, suggestive of lipoma of parotid gland [Figure 2].
The superficial parotidectomy of left parotid gland region was performed under general anesthesia during surgery, facial nerve was identified and preserved [Figure 3]a. The tissue specimen was sent for histopathological evaluation [Figure 3]b. The histopathological examination showed mature fat cells and scanty stroma. A focus of cystic degeneration seen surrounded by fibrocollagenous wall with cholesterol clefts and foamy macrophages [Figure 4]. Based on the above microscopic features, a final diagnosis of lipoma of left parotid gland was made. No postoperative complication or recurrence has been reported [Figure 5].
|Figure 3: (a) Intraoperative picture with yellowish fatty tissue and (b) Resected specimen|
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| Discussion|| |
Presence of adipose tissue in the parotid gland is well known, but the occurrence of lipoma in parotid gland is rare. Lipomas are the most common benign mesenchymal encapsulated tumors of which 25% of lipomas and their variants are observed in the head and neck region, and it rarely arises in the parotid region. Lipomas of the parotid gland have a male predilection (male to female ratio of 3:1) and it most frequently occurs in the fifth and sixth decades of life which is in accordance with the present case. Various etiological factors have been considered such as hereditary, trauma, diabetes, endocrine disorders, corticosteroids, obesity, and radiation.
Intraparotid lipomas usually occur in the superficial lobe (75%), whereas 8.5% cases occur in the deep lobe extending to the parapharyngeal space and about 16.5% of cases occur both in deep and superficial lobe on the inferior part of the parotid gland . Clinically lipomas appear as a slow-growing, painless, mobile, and well-differentiated mass in the parotid region which may be frequently confused with pleomorphic adenoma, Warthin's tumor, parotid cyst and benign mesenchymal neoplasms such as hemangioma and lymphangioma. Clinical examination is insufficient in all cases to identify the nature and location of parotid lipomas. Hence diagnosis of parotid lipoma is challenging, FNAC accompanied with CT scan and MRI determines its diagnosis preoperatively.
The preoperative imaging has a crucial role to correctly diagnose the nature and the location of lesions. Fine needle aspiration is an important diagnostic procedure towards detecting parotid tumors. However, its reliability is quite questionable to only 50% in most cases of parotid tumors.
CT scan and MRI can be helpful in giving information about pathological features of the tumors, to evaluate its location and its relation to important anatomic structures. In CT scan lipomas show a homogenous mass with few septations and less than water density with -50 and -150 HU densities which is characteristic of lipoma. However, CT scan does not help much in differentiation of lipoma from surrounding adipose tissue. MRI remains the best diagnostic technique that can accurately diagnose lipomas preoperatively by comparing the signal intensity on T1- and T2-weighted images. MRI can also clearly define the limits of lipoma from normal adipose tissue (subcutaneous tissue) with a “black-rim” around the mass.
Surgery is the treatment of choice of parotid gland lipoma, but its modalities remain controversial. The postoperative esthetic and functional results should be the major concerns. Most surgeons suggest a formal superficial parotidectomy with full exposure of the facial nerve and its branches for deep parotid lobe lipoma. Recurrence rate of lipoma after surgery is 5%, when the lesion is well capsulated.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]