|Year : 2013 | Volume
| Issue : 3 | Page : 118-121
Oral lipoma: An uncommon clinical entity
Suresh K Sachdeva1, Purnendu Rout2, Sanjay Dutta3, Pradhuman Verma1
1 Department of Oral Medicine and Radiology, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India
2 Kalinga Institute of Dental Sciences, Bhubaneswar, Odisha, India
3 Maharana Partap College of Dentistry and Research Centre, Gwalior, Madhya Pradesh, India
|Date of Web Publication||7-Feb-2014|
Suresh K Sachdeva
Department of Oral Medicine and Radiology, Surendera Dental College and Research Institute, Sri Ganganagar - 335 001, Rajasthan
Source of Support: None, Conflict of Interest: None
Lipoma is a benign mesenchymal tumor of mature fat cells. It is the most common mesenchymal tumor of the trunk and proximal portions of extremities. They account for the 0.5-5% of all benign tumors occurring in the oral cavity and hence presenting as an uncommon clinical entity intra-orally. In the oral cavity, they present as a slow growing, painless and asymptomatic yellowish sub-mucosal mass. Here is the case of a 45-year-old female, who presented with a growth in lower right buccal mucosal region. The purpose of this report is attempts to highlight the existence of this uncommon disease and to emphasis the need for dentists to be aware of frequency of occurrence of intraoral lipoma and hence that it is included in the differential diagnosis of oral soft tissue swellings.
Keywords: Buccal mucosa, female, lipoma, oral
|How to cite this article:|
Sachdeva SK, Rout P, Dutta S, Verma P. Oral lipoma: An uncommon clinical entity. J Oral Maxillofac Radiol 2013;1:118-21
| Introduction|| |
Lipoma is the most common soft-tissue benign mesenchymal neoplasm of fat cells, with 15-20% of cases involving the head and neck region, mostly the posterior neck region. They are relatively uncommon in the oral cavity (0.5-5% of all benign tumors).  Clinically, it is usually painless, slowly enlarging, soft, smooth-surface sub mucosal mass that may be located superficially or deeply. When it is superficial, it has a yellow surface tinge. The lesion may be pedunculated or sessile and occasionally with surface bosselation, located mainly in buccal mucosa, followed by the tongue, floor of mouth and lips.  Its differentiation from other mesenchymal tumors is mandatory for treatment planning and diagnosis. Here is a report of this uncommon clinical entity involving right buccal mucosa in a female patient along with clinical, imaging and histopathological features with no recurrence on follow-up.
| Case Report|| |
This was a case report of a 45-year-old female patient who presented to the Department of Oral Medicine and Radiology with the chief complaint of a painless swelling in the lower right cheek region since 2 years. There was no history of trauma or fever, with non-relevant past medical, social and family history. Past dental history included extraction of 46 one year back due to pulpal involvement. The growth did not interfere with mastication or speech. It was initially small and has grown to the present size. On general examination, the patient was of moderate built and height with mild obvious facial asymmetry extra-orally on the right side [Figure 1]. Regional lymph nodes were not palpable. Intra-oral examination revealed a single, well-defined, sessile growth in right buccal mucosal region extending from mesial aspect of 43 to distal aspect of 47, with smooth, faint yellow colored surface. The growth was oval, soft in consistency and non-tender, non-pulsatile, measuring around 5 cm × 3 cm in size [Figure 2]. Slipping sign was not demonstrable. On the basis of the history and clinical examination, a provisional diagnosis of benign soft-tissue tumor of right buccal mucosa was made. Differential diagnosis of intra-oral lipoma, fibroma, pyogenic granuloma and minor salivary gland neoplasm were considered.
|Figure 1: Extra-oral photograph showing facial asymmetry on right side of the face|
Click here to view
|Figure 2: Intra-oral photograph showing the smooth surfaced lesion in right buccal mucosa|
Click here to view
Routine investigations including complete blood count, serum urea and electrolyte and urinalysis were all within the normal limits. Conventional radiographic examination including cross-sectional mandibular occlusal mandibular view did not reveal any relevant findings [Figure 3]. On computed tomography (CT) scan revealed a well-defined homogeneously hypodense lesion on right side of mandible without any bony erosion with low attenuation value of -80 HU, measuring 4.5 cm × 2.5 cm [Figure 4].
|Figure 3: Cross-sectional mandibular occlusal view with no bone involvement|
Click here to view
|Figure 4: Axial computed tomography scan with well-defined hypodense lesion on buccal aspect of right mandible|
Click here to view
Lesion was surgically excised with intraoral approach and sent for histopathological examination [Figure 5]. Excised specimen floated in the formalin bottle [Figure 6]. Histopathological examination showed mature adipocytes, with clear cytoplasm and eccentric nuclei [Figure 7]. These features were consistent with a classical diagnosis of a lipoma. Hence the final diagnosis of intra oral lipoma of right buccal mucosa was made based on the clinical, imaging, surgical and histopathological findings. Patient is under follow-up and no recurrence has reported until yet.
|Figure 7: Photomicrograph showing empty adipocytes in connective tissue stroma (H and E, ×40)|
Click here to view
| Discussion|| |
Roux in 1848 was the first to describe the intra-oral lipoma, referring it as yellow epulis'.  Lipoma is a benign mesenchymal tumors of mature fat cells, with a uncommon presentation in the oral cavity. It is a true benign neoplasm because of its autonomous growth and unavailability of the fat to metabolism.  The peak incidence age for lipoma is 40 years or older (mean age = 51.9 years, range = 9-92 years). In the present case, the patient was of 45 years of age. In general their prevalence does not differ with gender; still male predilection has been reported.  The common site for oral lipoma is buccal mucosa, as was in our case, followed by the tongue, floor of mouth and lips. This pattern can be closely related to fat deposit in the oral cavity. The exact etiology is unknown, still heredity, trauma, hormonal factors, infection, infarction, chronic irritation are some of the suggested causes. Clinically, intraoral lipoma is a slow growing; painless, well-circumscribed sub mucosal mass with a yellowish tinge and duration of several years, as observed in our cases. These clinical features make other lesions with similar clinical findings, to be included in the differential diagnosis, such as oral dermoid and epidermoid cysts and oral lymphoepithelial cyst. Oral lymphoepithelial cyst is usually small at the time of diagnosis, occur in 1 st to 3 rd decade of life and the most common site of occurrence is the floor of the mouth, soft palate and pharyngeal tonsil. Oral dermoid and epidermoid cysts typically occur in the midline of the floor of the mouth. If the overlying mucosa of oral lipoma appears normal, then salivary gland tumors and benign mesenchymal neoplasms should be considered in the differential diagnosis. On transillumination test, lipoma has a less dense and more uniform appearance than the surrounding fibro vascular tissue. Oral lipoma of the buccal mucosa can be differentiated from a herniated buccal fat pad by the lack of a history of sudden onset after trauma. 
Usually the lipoma presents as single entity, but Cowden's syndrome is associated with multiple lipomas. 
In general, on conventional radiography, there is no alteration seen. On CT, lipomas have a pathognomic, homogeneous, non-enhancing, low attenuation value of -65 to -125 HU. This low attenuation helps in differentiation from other clinically similar lesions. Our case also had low attenuation value of -80 HU. Lipomas often displace and compress adjacent structures without infiltration.MR imaging of a typical lipoma demonstrates high signal intensity, consistent with fat on T1-weighted images and lower T2-weighted signal intensity, which may be minimally heterogeneous. An important diagnostic point is that whenever a lipoma has an overall heterogeneously dense matrix, it may represent a liposarcoma. 
A lipoma will float without sinking on the surface of formalin specimen jar. In the present case also, the specimen showed same characteristic, which is diagnostic of Lipoma, though the definitive diagnosis of Lipoma is based on the histopathology, showing mature fat cells, surrounded by a fibrous capsule. Depending upon the type and quantity of tissue, histological variants of lipoma includes simple lipoma, fibrolipoma, angiolipoma, myxolipoma, chondrolipoma. Most of these microscopic variations do not affect the overall good prognosis. The most frequent histological subtype in the oral cavity is simple lipoma, followed by fibro-lipoma. The present case was simple lipoma with mature fat cells in connective tissue stroma. The fat cells of lipomas are similar to surrounding normal fat cells but larger in size.  Furthermore lipomas usually have chromosomal aberrations such as translocations between 12q13-15, interstitial deletions of 13q and rearrangements of 8q11-13 locus. Microscopically, differential diagnosis includes liposarcoma which is characterized by pleomorphic cells, lipoblastic proliferation, myxoid differentiation, mitosis and increased vascularity. 
The treatment of oral lipoma, including all the histological variants is adequate surgical excision. The surgical approach depends on the site of the tumor and proposed cosmetic result, in this case the lipoma was approached intra-orally and no post-operative complication resulted, with excellent outcome and no recurrence on follow-up. Suction-assisted lipectomy has also been reported for the treatment of lipoma. 
| Conclusion|| |
Oral lipomas are uncommon benign tumors. The clinical course is usually asymptomatic until they get larger in size. Sometime it is difficult to differentiate between Lipoma and other similar appearing lesion, but the characteristic floating on formalin solution and low attenuation on CT scan helps in making a correct diagnosis.
| Acknowledgement|| |
We would like to acknowledge Dr. S. Jayachandran, Prof. and Head, Department of Oral Medicine and Radiology, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India for his contribution in data collection and manuscript review.
| References|| |
|1.||Fregnani ER, Pires FR, Falzoni R, Lopes MA, Vargas PA. Lipomas of the oral cavity: Clinical findings, histological classification and proliferative activity of 46 cases. Int J Oral Maxillofac Surg 2003;32:49-53. |
|2.||Studart-Soares EC, Costa FW, Sousa FB, Alves AP, Osterne RL. Oral lipomas in a Brazilian population: A 10-year study and analysis of 450 cases reported in the literature. Med Oral Patol Oral Cir Bucal 2010;15:e691-6. |
|3.||Rajendran R. Shafer's Oral Pathology. 5 th ed. Amsterdam: Elsevier; 2006. p. 194-5. |
|4.||Miles DA, Langlais RP, Aufdemorte TB, Glass BJ. Lipoma of the soft palate. Oral Surg Oral Med Oral Pathol 1984;57:77-80. |
|5.||Furlong MA, Fanburg-Smith JC, Childers EL. Lipoma of the oral and maxillofacial region: Site and subclassification of 125 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:441-50. |
|6.||Som PM, Curtin HD. Head and Neck Imaging. 4 th ed. St. Louis, Missouri: Mosby; 2003. p. 1415-6. |
|7.||de Castro AL, de Castro EV, Felipini RC, Ribeiro AC, Soubhia AM. Osteolipoma of the buccal mucosa. Med Oral Patol Oral Cir Bucal 2010;15:e347-9. |
|8.||Kaur R, Kler S, Bhullar A. Intraoral lipoma: Report of 3 cases. Dent Res J (Isfahan) 2011;8:48-51. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]