CASE 14358 Published on 08.05.2017

Sub-mucous lipoma along alveolar process of mandible and gingivobuccal vestibule

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Dr Ami Jani

Resident Doctor
B.J. Medical college,
Civil Hospital Ahmedabad,
Civil hospital road,
Asarwa 079 380016, Ahmedabad;
Gujarat, India;
Email:janiami16@gmail.com
Patient

32 years, female

Categories
Area of Interest Head and neck ; Imaging Technique CT, Experimental
Clinical History
A 32-year-old male patient presented with a longstanding (3-4 year) history of left cheek swelling. The lesion was gradually increasing in size. On examination it arose from the alveolar process of the mandible, related to the left canine and premolars.
Imaging Findings
Ultrasound examination was performed with a 6.5 MHz probe extra-orally which showed a well-defined encapsulated lesion isoechoic to subcutaneous tissues. To understand its anatomical relationships a non-contrast CT of the face was performed.
On CT a well-defined homogeneous fat density lesion, measuring approximately 2.7 x 3.5 x 3 cm was seen arising from the mucosa of the alveolar process of the mandible related to the left canine and premolars, and the gingivobuccal sulcus. There was no evidence of internal necrosis or calcification. Underlying bone appeared normal with no evidence of erosion or extension into surrounding soft tissues.
Discussion
Background: A lipoma is a benign well-encapsulated lesion that consists of adipose tissue. It can arise from any organ of the body and may be confused with other locoregional mass lesions. Oral mucosal lipomata are rare, accounting for 1-4 % of lipomata [1, 2].
Clinical Perspective: Lipomata present with swelling and are typically slowly growing lesions. On examination they are soft and characteristically show a 'slipping sign'- their margins 'slip' under the tip of the finger on palpation. In submucosal lipomata, overlying mucosa normally appears unremarkable [3].
Imaging Perspective: OPG shows normal teeth with a soft tissue mass. Ultrasound demonstrates a well-defined encapsulated mass lesion isoechoic to subcutaneous tissues. Non-contrast CT will show a well-defined homogeneous fat density lesion. In the absence of complications, non-contrast CT will suffice to make the diagnosis. Most oral lipomata do not show any complications. However, inhomogeneous density on NCCT needs further evaluation. Contrast-enhanced CT is indicated when the overlying mucosa and underlying bone of long-standing lipoma develop superadded infection.
MRI may also be used to image such lesions, with signal characteristics following fat on all sequences.
Outcome: Lipomata can be diagnosed clinically. Oral submucous lipomata are rare. To rule out other lesions of the oral mucosa and buccal vestibule, imaging may be performed. The differential includes haemangioma, mucus retention cyst-mucocele, and abscess secondary to dental infection [2]. NCCT or MRI are usually sufficient for differentiating lipomata from other lesions. Homogeneous fat density confirms the diagnosis.
Most reported intraoral lipomata are uncomplicated. The risk of malignant transformation is unproven. There has been debate regarding the malignant potential of intramuscular lipomata. In a review of the literature, Matsumoto has reported a case of liposarcoma with multiple coexisting intramuscular lipomata suggesting malignant transformation of latter [4]. However, many studies have not found any such correlation [4]. Large lesions may be subject to repeated trauma and ulceration. Such ulcers can simulate malignancy. However, in the case presented the mucosa was intact.

Treatment: Surgery is the treatment of choice in symptomatic cases, usually performed under local anaesthetic.
Differential Diagnosis List
Submucous lipoma of the mandibular alveolar process and buccal vestibule
Mucous retention cyst
Osteoma of mandible
Infected dental root
Dentigerous cyst
Haemangioma
Final Diagnosis
Submucous lipoma of the mandibular alveolar process and buccal vestibule
Case information
URL: https://www.eurorad.org/case/14358
DOI: 10.1594/EURORAD/CASE.14358
ISSN: 1563-4086