Case Report: Buccal Lipoma, A Rare Entity

By: Dr. Dheeraj V. Mulchandani and Dr. Manmal Manikchand Begani

Introduction

Although they are supposed to be one of the most common benign mesenchymal neoplasms [1] presenting as soft tissue swellings encountered in general surgical practice, lipomas occurring in the oral cavity remain relatively rare occurrences with the data suggesting only 15-20% occur in the head and neck region [3]. However, only 1% to 4% occur in the oral cavity [3,4].

Adequate surgical excision in order to prevent recurrence is the treatment of choice [1,5].

This is a case report of a 42-year-old woman who presented with a slow growing left cheek swelling that was treated by intra-oral local excision under local anaesthesia in a day care surgical set up.

Case presentation

A 40 year old fisherwoman presented to our day care surgery with her complaints of a slowly progressive swelling originating over the inside of her left cheek. It was relatively painless with the only mass effect as the presenting complaint.

There was no history of trauma and the swelling was not associated with fever, weight loss or any other otorhinolaryngological symptoms. She was a chronic user of Tobacco powder for cleaning her teeth. Examination revealed a 4 cm by 3 cm non-tender, smooth, mobile, firm mass in the left cheek with no skin changes. There was no bruit over this mass. The intra-oral mucosa over the mass appeared normal. A differential diagnosis of lingual thyroid, buccal soft tissue lipoma and epidermoid cyst was made.
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Imaging using ultrasonography revealed an oval-shafted echopoor solid mass just underneath the buccal mucosa measuring about 25mm X 12mm X 20mm. Other investigations performed included full blood count, serum urea and electrolyte, and urinalysis which were all within normal limits. Thyroid function tests revealed a high TSH level which prompted us to treat with thyronorm for 15 days to watch for levels and rule out hypothyroidism and lingual thyroid. An Ultrasound of the neck was performed to rule out absent thyroid gland in its normal anatomical location. The neck Ultrasound was normal with presence of a reactive lymph node in the right midjugular chain. The patient was advised a Radioactive Iodine Uptake Thyroid Scan and a Computerized Tomographic scan both of which were not done because the patient could not afford to pay for it.

She was prepared for and had excision of the mass under local anaesthesia in our day care set up. During surgery, the mass was approached intra-orally by a transverse 4 cm linear incision made directly over the mucous lining over it (Figure 1). The 3 cm X 3 cm irregular yellowish mass (Figure 2) was carefully excised de novo and the wound was closed using a chromic 3/0 Catgut suture.

Figure 1: Lipoma being excised via an intra-oral incision.

Figure 2: Excised lipoma.

The excised specimen was sent for Microscopic examination which revealed benign lesion comprising of sheets of mature adipocytes containing large clear cytoplasm and eccentric nuclei with inconspicuous vascularity and no evidence of cellular atypia or metaplasia (Figure 3). These features are consistent with a classical diagnosis of a lipoma.

Figure 3: Photomicrograph showing aggregates of mature adipocytes with large clear cytoplasm and eccentric nuclei. Hematoxylin and eosin stain ×20.

Postoperatively, she was monitored for about 2 hours after which she was discharged home having been placed on ciprofloxacin, ibuprofen sos for pain and betadine oral mouth wash after meals. She was followed up on the 1st, 3rd and 7th Post operative day and the wound was found to be healing well. A long term follow up for recurrences has been recommended.

Discussion

Lipomas are the most common benign adipose mesenchymal neoplasms that only rarely occur in the oral cavity with a reported incidence of 1% to 4% [3,4]. Roux, in 1848, described the first oral lipoma in literature and he referred to it as “Yellow Epulis”.

Most lipomas occurring in the maxillofacial region are developmental and usually occur late in life. The peak incidence age for lipoma is 40 years and above [5]. Generally, their prevalence does not differ with gender, although a male predilection has been recorded [6]. A few of the lipomas show rearrangement of 12q, 13p, and 6p chromosomes. [*3,4]. It has been suggested that trauma may, sometimes, acts as a trigger mechanism for the proliferation of the existing adipose tissue to convert into a lipomatous swelling [7].

The classification for benign lipomas includes the following: classic lipoma; lipoma variants (for example angiolipoma, chondroid lipoma, myolipoma, spindle cell lipoma); hamartomatous lesions; diffuse lipomatous proliferations and hibernoma [8].

In the oral cavity, the most common sites for lipomas are the cheek, tongue, palate, mandible and lip. They may occur as either sessile or encapsulated masses [2, 6].

Clinically, oral lipomas present as soft nodular swellings, usually of a long-standing nature based on them being slow growing tumors [9]. They are almost always covered by normal appearing overlying mucosa.

They are well defined masses clinically as well as radiologically using Ultrasonography and Computerized Tomographic scan [10] and more recently, using Magnetic Resonance Imaging [11].

A differential diagnosis is essential in these cases as they tend to have varying modes of presentation. The commonly made differential diagnosis besides that of a classic lipoma are those of an epidermoid cyst, dermoid cyst, lymphoepithelial cysts, and in rare cases aberrant lingual thyroid tissue [13].

Oral dermoid and epidermoid cysts usually occur over the midline of the floor of the mouth [15] but can also occur in other sites of the oral mucosa [4].

Lymphoepithelial cysts are found in the floor of the mouth, soft palate and mucosa of the pharyngeal tonsil [14].

Aberrant thyroid tissue can be easily ruled out using a combination of an Ultra sonogram of the neck to determine presence of normal functioning thyroid gland along with a Radioactive Thyroid Scan to detect presence of active thyroid tissue elsewhere in the body. FNAC of the swelling may be recommended in highly suspicious cases but is usually not necessary.

Usually, it is cosmesis that brings a patient to the surgery in cases of asymptomatic swellings leading to a prolonged course beforehand. In rare cases, complications may ensue, for e.g. obstruction to airway in cases of pharyngeal / esophageal fibrolipomas [17], or in long standing cases malignant transformation to liposarcoma is a possibility [18].

Adequate surgical excision is the treatment of choice for oral lipomas [1,5]. The surgical approach is dependent on the site of the tumor and the proposed cosmetic result. Our patient’s lipoma was approached intra-orally by a transverse 5 cm linear incision made directly over the mucous lining over it. Microscopically, it is difficult to differentiate between normal adipose tissue and lipomas, therefore, a clinician sending a surgical specimen to the pathologist for microscopic analysis must provide accurate clinical and surgical information in order to make a definitive diagnosis [4]. The microscopic appearance of a circumscribed but not encapsulated aggregate of mature adipocytes with large clear cytoplasm in the absence of vascularity, atypia or metaplasia is diagnostic of a classical lipoma.

Conclusion

Buccal soft tissue lipomas are rare tumors. A high index of suspicion is required in making a diagnosis. Surgical excision is the ideal treatment with excellent outcome. Supported with the correct investigations, the entity can be tackled easily in a day care setting without the need for overnight hospitalistion. The importance of histological diagnosis cannot be overemphasized and the features of lipoma are usually straightforward and classical.

About The Author

Dheeraj MalchandaniDr. Dheeraj V. Mulchandani M.B.B.S., M.S., D.M.A.S. F.A.L.B.S. is currently an Associate Consultant in General and Laparoscopic Surgery and Hospital Administrator in South Mumbai.  He also has an M.B.A. in Corporate Management in Healthcare and Hospital Administration and is the Medical Director for Dr. Mulchandani’s Medical Services.

 

About The Author

Dr. Manmal Manikchand Begani M.B.B.S., M.S. is currently a Consultant Surgeon at Bombay Hospital, Associate Professor at Bombay University (BHIMS), Medical Director for Abhishek Day Care Institute & Medical Research Centre and Consultant Surgeon at Saifee Hospital Bombay.

 

References (click to show/hide)

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  18. Riebel J F and Green W M. Liposarcoma arising in the pharynx nine years after fibrolipoma excision. Otolaryngology Head Neck Surg. 1995; 112: 599-602.

Consent: Written informed consent was obtained from the patient for publication of this case report and any accompanying images.
Competing interests: The authors declare that they have no competing interests.
Acknowledgements: The authors are grateful to the consultant anesthesiologist who was involved in the surgery of this patient as well as the pathologist who delivered the slide photograph. We also thank the patient for giving her consent to report this case.


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