A rare presentation of lipoma on mandibular mucogingival junction

Abstract

Lipoma is the most common tumor of mesenchymal tissues of body, but its occurrence in oral cavity is infrequent. Buccal mucosa is the most common intraoral site of lipoma followed by tongue, floor of the mouth, and buccal vestibule. The involvement of mucogingival junction is rare. We present a unique case report of oral lipoma occurring on mandibular mucogingival junction with review of literature which has emphasis on differential diagnosis. © 2016 Indian Society of Periodontology | Published by Wolters Kluwer - Medknow.

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© 2016 Indian Society of Periodontology | Published by Wolters Kluwer ‑ Medknow 199
Address for
correspondence:
Dr. Gaurav Sharma,
Department of Oral
Medicine and Radiology,
Sudha Rustagi Dental
College, Faridabad,
Haryana, India.
E‑mail: drgaurav7479@
rediffmail.com
Submission: 07‑10‑2014
Accepted: 12‑10‑2015
Departments of Oral
Medicine and Radiology,
Sudha Rustagi College
of Dental Sciences and
Research, Faridabad,
Haryana, 1Oral and
Maxillofacial Pathology,
Jaipur Dental College,
Jaipur, Rajasthan,
2Oral Medicine and
Radiology, P.D.M.
Dental College,
Bahadurgarh, Haryana,
3Periodontology, Sudha
Rustagi College of
Dental Sciences and
Research, Faridabad,
Haryana, India
A rare presentation of lipoma on
mandibular mucogingival junction
Gaurav Sharma, Kanu Jain,1 Archna Nagpal,2 Chandrababu Sudha Baiju3
Abstract:
Lipoma is the most common tumor of mesenchymal tissues of body, but its occurrence in oral cavity is infrequent.
Buccal mucosa is the most common intraoral site of lipoma followed by tongue, oor of the mouth, and buccal
vestibule. The involvement of mucogingival junction is rare. We present a unique case report of oral lipoma
occurring on mandibular mucogingival junction with review of literature which has emphasis on differential
diagnosis.
Key words:
Diagnosis, differential, lipoma, mucogingival junction
INTRODUCTION
Lipomas are most common benign neoplasms
of mesenchymal tissues accounting for their
15–20% of cases occurring in head and neck
region, while only 1–4% cases seen intraorally.[1,2]
The etiology and pathogenesis of lipoma is not
clear, but many factors such as mechanical,
endocrine, and inammatory inuences have
been reported inconclusively for their role.[1,3] In
oral cavity, lipomas are observed during routine
intraoral examination and usually involve areas
with fat accumulation.[2] Clinically, lipomas are
slow growing asymptomatic painless nodular
swellings with either yellow color or that of
normal mucosa.[2] Intraorally, most commonly
involved sites are buccal mucosa, tongue, oor
of the mouth, buccal vestibule, and lips.[3,4] We
here present a rare case of lipoma occurring on
mandibular mucogingival junction, an extremely
rare intraoral site for lipoma with focus on
differential diagnosis.
CASE REPORT
A 32-year-old male patient reported with the
complaint of painless swelling in left mandibular
posterior region since 4 months that was
gradually increasing. The patient had no history
of dysphagia, difficulty in speaking, and no
previous episode of swelling in the same region.
The patient had not undergone any treatment for
the swelling and not taken any medication. There
was no signicant family and medical history.
No obvious facial swelling or lymphadenopathy
was observed. The intraoral swelling measuring
12 mm × 18 mm approximately was observed
on the left mandibular mucogingival junction
extending from the second premolar to third
molar [Figure 1]. Swelling was of same color to
that of normal adjacent mucosa. There was no
pus or blood discharge from the swelling and
no ulceration. On palpation, swelling was soft
in consistency with smooth margins and not
xed to underlying deeper structures. A slight
compressibility was observed in the swelling and
was nontender. Intraoral periapical radiograph
revealed normal trabecular bone structure
and no pathological changes were observed in
alveolar bone [Figure 2]. Based on the history
and clinical examination, a provisional diagnosis
of intraoral benign soft tissue tumor was given.
It was surgically excised by excisional biopsy
and was sent for histopathological examination.
The hematoxylin- and eosin-stained soft tissue
specimen showed the presence of sheets of mature
adipocytes in a distinct lobular arrangement with
a thin brous capsule [Figure 3]. The mature
adipocytes demonstrated large clear cytoplasms
and eccentric nuclei [Figure 4]. There was no
evidence of cellular atypia. Based on the above
ndings, a nal diagnosis of lipoma was made.
The patient was recalled after 1 week for suture
removal. The wound had healed uneventfully.
No signs of recurrence were seen at a follow-up
for 6 months.
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DOI:
10.4103/0972‑124X.170827
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How to cite this article: Sharma G, Jain K, Nagpal A,
Baiju CS. A rare presentation of lipoma on mandibular
mucogingival junction. J Indian Soc Periodontol
2016;20:199‑202.
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Case Report
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Sharma, et al.: Oral lipoma
200 Journal of Indian Society of Periodontology ‑ Vol 20, Issue 2, Mar‑Apr 2016
DISCUSSION
Lipomas are mesenchymal tumors of adipose tissue. They
commonly involve trunk and proximal portions of extremities
and are relatively uncommon in oral cavity. They account for
0.5–5% of all benign tumors of oral cavity.[1,2] The etiology is
still not clear, but a role of various factors has been reported.[3]
According to “hypertrophy theory” these tumors occur in oral
cavity due to obesity and inadvertent growth of adipose tissue.
However, it cannot explain lipomas occurring at sites devoid
of fat. However, “metaplasia theory” states that aberrant
differentiation of mesenchymal cells into lipoblasts leads to
the development of lipoma.[4] It is thought that trauma and
chronic irritation may trigger the proliferation of fatty tissue
that can cause development of lipoma.[5]
Mean age of occurrence of intraoral lipoma varies according
to different studies, but they usually occur in fourth and fth
decades of life.[6] The occurrence of lipoma is uncommon
in children.[7] Their prevalence is similar in both the sexes,
although a male and female predominance has also been
recorded.[4,5] The present case of lipoma was seen in a male
patient with age of 32 years. Most common intraoral sites are
buccal mucosa, tongue, oor of the mouth, vestibule, and lip.
In a study by Taira et al., lipoma on gingiva was found in only
8.7% of the cases out of 207 cases of oral lipoma, suggesting it
to be an uncommon site of occurrence.[8] Manor et al. could not
document any case of gingival lipoma in an analysis of 58 cases
of oral and maxillofacial lipomas.[9] Studart-Soares et al. had
documented gingiva to be the rarest intraoral site for lipoma
in their extensive analysis of 450 cases of lipoma.[10] Dattilo
et al. also had reported the periodontium to be a rare site of
intraoral lipomas.[11] A case of lipoma occurring on mandibular
mucogingival junction was recently reported.[12]
Oral lipomas clinically may present as slow growing solitary or
multiple lesions which may be sessile or pedunculated.[1,5] They
present as asymptomatic, well-circumscribed soft encapsulated
fluctuant masses or nodules with doughy consistency.[2]
Grossly, the color may vary from that of normal mucosa
to pink and some may present as yellowish masses. The
diagnosis is not easy if the yellow color of the tumor is not
visible through overlying thin mucosa.[13] Size of the tumor
varies and depends on the location. In a study, size as large
Figure 1: Intraoral swelling in left mandibular posterior region Figure 2: Intraoral periapical radiograph revealing normal trabecular bone pattern
Figure 3: Photomicrograph showing sheets of mature adipocytes in a distinct
lobular arrangement with a thin brous capsule, A = adipocyte, C = capsule.
(H and E, ×100, scale bar = 25 μm)
Figure 4: Photomicrograph showing mature adipocytes demonstrating large
clear cytoplasms and eccentric nuclei, A = adipocyte, *represents blood capillary.
(H and E, ×400, scale bar = 5 μm)
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Sharma, et al.: Oral lipoma
Journal of Indian Society of Periodontology ‑ Vol 20, Issue 2, Mar‑Apr 2016 201
as 8 cm has also been reported.[7] Although the growth of oral
lipomas is usually limited, they can reach great dimensions,
interfering with speech and mastication, reinforcing the
need for excision.[2] In our case, the patient presented with a
solitary soft sessile smooth mass measuring 12 mm × 18 mm
approximately. The complications typically associated with
lipomas have been functional impairment due to giant size
that they achieve occasionally. No neurological complications
have been reported yet.
Because of the similar clinical presentation, lesions such as oral
dermoid and epidermoid cysts, oral lymphoepithelial cyst,
benign salivary gland tumor, mucocele, benign mesenchymal
neoplasm, ranula, ectopic thyroid tissue, and lymphoma are
considered in its differential diagnosis. In our patient, the
possibility of broma was excluded as the swelling was soft
in consistency. The possibility of a dermoid or epidermoid
cyst was also excluded as the location was not in favor.
Hemangioma, lymphangioma, rhabdomyoma, neuroma, or
neurobromas are the swellings to be ruled out when tumor is
located on dorsal surface of tongue.[4] Although oral lipomas
are well-circumscribed soft tissue lesions, rarely they give a
radiographic impression of an intraosseous neoplasm within the
mandibular canal.[14] Lipomas may show radiographic features
rarely manifesting as radiolucency.[10] The gross specimen of
lipoma when placed in a pot with water usually oats in it.[3] It
is difcult to distinguish lipoma from surrounding connective
tissue when it is deeply placed. Fine-needle aspiration
biopsy (FNAB) or Ultrasound –guided FNAB sometimes can
be used for aspiration in such cases. Ultrasonography is a
preferred technique as it is faster and inexpensive, and lipomas
are hypoechoic with echogenic spots.[15] Magnetic resonance
imaging can be used to nd the anatomical extent of intraoral
tumors.[15] A color Doppler ultrasonography can also be done
to evaluate the content of the lesion and its vascularity.[15] The
prognosis of oral lipomas is good and recurrence rarely occurs.
Histopathology remains the gold standard in the diagnosis
of lipoma. The histopathological features constitute of a
circumscribed aggregate of mature adipocytes which may be
encapsulated. Adipocytes show large clear cytoplasm in the
absence of vascularity which serves as diagnostic feature of
classic lipoma.[6] All lipomas are usually well-vascularized, but
the vascular network is compressed by the distended lipocytes
and is usually not appreciable.[16] The hematoxylin- and
eosin-stained soft tissue specimen in our case showed
the presence of mass of mature adipocytes arranged in
lobules surrounded by a brous capsule. Adipocytes have
large empty cytoplasms with eccentrically placed nuclei.
There was no evidence of cellular atypia. On the basis of
microscopic features, lipomas can be classified as simple
lipoma, brolipoma, inltrating or intramuscular lipoma,
angiolipoma, myxolipoma, spindle cell lipoma, pleomorphic
lipoma, myolipoma, angiomyolipoma, chondroid lipoma,
osteolipoma or ossifying lipoma, and salivary gland
lipoma (sialolipoma).[2] Histopathologically, the differential
diagnoses are normal soft fatty tissue, other histologic variants
of lipoma and liposarcoma.[6] Other lesions which should
be distinguished are schwannoma, myxoid neurobroma,
leiomyoma, nodular fasciitis, myxolipoma, fibrolipoma,
malignant brous histiocytoma, myxoid liposarcoma, and
myxoid solitary brous tumor.[15] Despite the close histological
similarity to normal adipose tissue, lipomas, usually, have
chromosomal aberrations such as translocations involving
12q13-15, locus interstitial deletions of 13q, and rearrangements
involving 8q11-13 locus.[17] Immunohistochemistry has been
used for differentiation between benign and malignant adipose
tissue tumors with detection of aP2, a protein expressed
by lipoblasts.[10] Immunocytochemical studies with CD34,
bcl-2, 21, 24 assists in differentiating lipomas from other
myxoid lesions.[18] However, immunohistochemistry was
not done in our patient due to nancial constraints and the
histopathological diagnosis was denite and in accordance
with clinical ndings.
Approximately, 5–8% of lipoma patients may present with
multiple tumors which occur predominantly in upper half of
the body and are three times more common in men than in
women. The term lipomatosis has been used to describe this
condition.[17] In our patient, there was no history or presence
of multiple swellings. The occurrence of multiple lipomas
can be seen in association with Cowden’s syndrome or
multiple hamartoma syndrome, Frohlich syndrome, Proteus
syndrome, and Bannayan–Zonana syndrome.[2,17] Most
common mucocutaneous lesions in the patients with Cowden’s
syndrome are small papular lesions in palate and gingiva,
papillomatous and verrucous lesions of buccal mucosa,
ssured tongue, and multiple cutaneous lipomas.[2] Frohlich
syndrome also known as prune belly syndrome is dened by
multiple lipomas, obesity, and sexual infantilism.[17] Proteus
syndrome is marked by multiple lipomatous lesions, including
pelvic lipomatosis, fibroplasia of feet and hands, skeletal
hypertrophy, exostoses and scoliosis, and various pigmented
lesions of skin.[17] A case of congenital lipoma was described in
a 7-year-old boy in upper labial frenum.[3] Bannayan–Zonana
syndrome is characterized by congenital association of multiple
lipomas, hemangiomas, and macrocephaly.[17]
The main treatment modality for intraoral lipomas and its
histologic variants is simple surgical excision.[16] Recurrence
rate described after excision is low, but inltrative lipoma
tends to recur after inadequate excision due to the fact that
they are not encapsulated like simple lipomas.[2] Steroid
injections are used when size of tumor is < 1 inch in diameter
and their usage results in local fat atrophy and hence shrinks
the size of tumor.[4] Malignant transformation is rare and
has been reported, especially for intramuscular lipomas.
Malignant tumors are characterized by areas of lipoblastic
proliferation, myxoid differentiation, cellular pleomorphism,
increased vascularity, and mitosis.[10] Thus, lipomas should be
excised completely as there is a rare possibility of malignant
transformation.
CONCLUSION
Intraoral lipomas are uncommon tumors which may arise in
any site in oral mucosa. However, the occurrence of lipoma on
mucogingival junction is rare entity. Patients usually do not
seek treatment for oral lipoma as it is mostly asymptomatic and
may be observed during routine oral examination. Although
the features of lipoma are simple and straightforward, accurate
clinical and surgical information along with a histopathological
examination is the mainstay to its denitive diagnosis. The
possibility of multiple lipomas must be considered and an
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Sharma, et al.: Oral lipoma
202 Journal of Indian Society of Periodontology ‑ Vol 20, Issue 2, Mar‑Apr 2016
accurate upper body examination must be done in patients
with intraoral lipomas. Clinicians should be aware about the
possibility of lipomas in the oral cavity and should always
consider it in their differential diagnosis of an inoffensive
swelling in oral cavity.
Financial support and sponsorship
Nil.
Conicts of interest
There are no conicts of interest.
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