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OJHAS Vol. 9, Issue 4:
Oct-Dec, 2010) |
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| Intramuscular (infiltrating)
Lipoma |
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P Sridhar Reddy, Department of Oral & Maxillofacial Surgery,
Ananth Naag, Department of Oral & Maxillofacial Surgery,
Bina Kashyap, Department
of Oral Pathology,
St. Joseph Dental College & Hospital, Duggirala, Eluru, Andhra Pradesh, India. |
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Address For Correspondence |
Flat no. 202, Sai Balaji Estates,
Gurukrupa Road,
Satavahana Nagar,
Eluru, West Godavari
District,
Andhra Pradesh, India.
E-mail:
padalasri@yahoo.co.in |
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Reddy PS, Naag A, Kashyap B. Intramuscular (infiltrating)
Lipoma. Online J Health Allied Scs.
2010;9(4):23 |
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Submitted: Oct 26,
2010; Accepted Nov 10, 2010; Published: Jan 20, 2011 |
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| Abstract: |
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Intraoral lipomas
are benign and relatively rare tumors, although they occur with higher
frequencies in other areas, most especially the back, abdomen and shoulders
of adults. They have no gender predilection and predominantly affect
the buccal mucosa. This paper describes a case of intramuscular (infiltrating)
lipoma on the buccal mucosa of a 60-year old male which is relatively
rare when compared to simple lipoma of buccal mucosa, and review pertinent
literature.
Key Words: Lipoma; Benign;
Intramuscular; Infiltrating
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Lipomas are
benign mesenchymal neoplasms composed of mature adipocytes, usually
surrounded by thin fibrous capsule.(1) They are the most common soft
tissue tumors and about 15 20% of cases occur in head and neck region.
However, its occurrence in the oral cavity is rare, it accounts only
14% of all lipomas affecting predominantly the buccal mucosa, floor
of the mouth and tongue. The unusual intraoral sites include the lips,
gingiva and palate.(2)
Generally oral
lipomas have been reported to occur in all ages but are frequently seen
after 40 years of age with peak occurrence in the fifth or sixth decades
of life.(3) The exact etiology remains unknown, although trauma, infection
and other factors have been proposed as etiological agents for lipomas.
They usually present as painless, well circumscribed, slow growing pedunculated
or sessile, submucosal or superficial lesions. Most of the diagnoses
were made clinically as they rarely give a radiographic impression but
imaging can be useful in the diagnosis and delimitation of oral lipomas.
Microscopically,
it is not possible to distinguish these lipomas from normal adipose
tissue, despite their different metabolism, probably due to high lipoprotein
lipase activity in neoplastic lipoma cells.(4) The most common lesions
were simple lipomas and fibrolipomas and rarer variants included angiolipoma,
intramuscular (infiltrating) lipoma, pleomorphic lipoma, spindle cell
lipoma, salivary gland lipoma (sialolipomas), myxoid lipoma and atypical
lipomas.(5,6) We report a patient with an intramuscular/ infiltrating
lipoma in the buccal mucosa which are relatively rare and also review
the international literature concerning about the clinical presentation,
microscopical characteristics, differential diagnosis and treatment.
A 60 year
old male complained of a left sided swelling in the buccal mucosa.
The lesion had appeared 10 years previously, growing very slowly and
without any accompanying symptoms of oral intake or speech. Oral examination
revealed non tender, large, well demarcated, smooth, sessile with
soft to firm mass of size 3 X 3 cm protruding from the left buccal mucosa.
The overlying mucosa appeared normal (Figure 1). There was no palpable
cervical lymphadenopathy. Medical history of the patient was non contributory.
Routine hemogram, ECG and X-ray chest were all within normal limits.
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Figure
1: Preoperative showing large mass on the buccal mucosa |
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Figure 2: Intraoperative. |
Excisional
biopsy of the mass was performed under local anesthesia (Figure 2).
At gross examination, specimen was polypoid to round in shape and measure
3 X 3 cm. Upon formalin fixation and paraffin embedding, sections were
treated with haematoxylin eosin. Microscopic examination showed
an intact stratified squamous epithelium covering the surface. The submucosa
revealed mature adipocytes extending to the epithelial level and which
lie down through the irregular bundles of skeletal muscle fibers, along
with few areas of vascularization. No cellular atypia, necrosis, mitotic
activity and lipoblastic proliferation was observed (Figure 3). The
patient had no perioperative problems and is without evidence of recurrence.
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Figure
3: Photomicrograph of H& E section showing infiltration of adipocytes
into the muscles under 10X. |
Lipomas are
common, benign tumors located in any part of the body in which fat is
normally present. They are relatively uncommon in the oral cavity, representing
about 0.5% to 5% of all benign oral tumors. Generally, their prevalence
does not differ with gender, although a predilection for men has been
reported.(7)
Lipomas generally
grow slowly because pain is not a feature in many cases, many years
elapse before patients consult their dentist or physician.(8) It bears
variable sizes from small 10mm masses to few large case series of 25 cm that have been published in the English language literature.
The present case reports the relatively rare large size of the lesion.
Clinical diagnosis
of oral lipomas is not always easy. Where the overlying mucosa is thin
and the yellow color of the tumor appears through it, the diagnosis
is easily made. However, in the deep seated cases, the diagnosis is
seldom made clinically and the tumors often attain appreciable size
before they cause symptoms and their presence recognized.(9,10) In such
situations, other possibilities such as cyst, an encapsulated abscess
or other benign tumors have to be considered. The case reported here
shows the difficulty that can be encountered in diagnosing deeply embedded lipoma. The deep position of this lesion suggested other possibilities
such as neurofibroma, fibroma, salivary gland tumor and lipoma.
The occurrence
of multiple lipomas is associated with cowdens syndrome or multiple
hamartoma syndrome. This condition is either familial or sporadic and
is associated with the predominantly post pubertal development of a
variety of cutaneous, stromal and visceral neoplasms, resulting from
mutation of the phosphatase and tensin homolog (PTEN) gene.(11) It
can involve various organs, such as the skin, oral mucous membrane,
thyroid, breast, ovaries and central nervous system. No such abnormality
was observed in the present case.
Histologically,
lipomas can be classified as simple lipomas or its variants namely fibrolipomas,
angiolipoma, intramuscular (infiltrating) lipoma, pleomorphic lipoma,
spindle cell lipoma, salivary gland lipoma (sialolipomas), myxoid lipoma
and atypical lipomas.(9) Although the clinical appearance of color
and tissue consistency may vary with the combination of histologic features,
such combinations are not of prognostic significance.(12)
Intramuscular
lipomas are of primary importance because of their differential diagnosis
with liposarcomas due to its large size, deep location and their ability
to infiltrate adjacent muscles and recur locally. Therefore, detailed
histological examination is essential in all intramuscular lipomas,
which can be commonly misdiagnosed as liposarcoma. Differential diagnostic
crieteria were summarized in Table 1. The intramuscular lipoma is usually
well demarcated, but has no capsule and infiltrates into the adjacent
muscle. Our case had no areas of lipoblastic proliferation, nuclear
atypia and mitosis. Although intramuscular or infiltrative lipomas are
recognized as a histologic subtype there is speculation that they are
simply lipomas with entrapped muscle fibers.(9)
The treatment
of oral lipomas, including all the histologic variants, is simple surgical
excision. No recurrence is observed except intramuscular lipomas. The
recurrence rate for infiltrating lipomas has been reported to be 3 to 6.5%.(13,14) They have propensity to recur without adequate surgery. Long term follow up
was recommended and so far, after 1 year our patient is free of disease
Lipomas are
the most common neoplasms of the soft tissue. They are only presenting
0.5 to 5% of all the benign neoplasms of the oral cavity. The most common
histologic subtype is the simple lipoma which predominantly affects
the buccal mucosa. Intramuscular (infiltrating) lipoma of the buccal
mucosa is a rare variant of lipoma and a few cases have been reported,
with same histologic and clinical appearance, well differentiated liposarcoma
must be excluded and surgical excision should be carefully done.
- Carter TG, Egbert
M. Traumatic proplase of the buccal fat pad (Traumatic Pseudolipoma):
A case report and literature review. J Oral Maxillofac Surg 2005;10291032.
- Akbulut M, Aksoy
A, Bir F. Intramuscular lipoma of the tongue: A case report and review
of the literature. Aegean Pathology Society 2005;2:146149.
- Morais HH, Vajgel
A, Rocha NS et al. Congenital lipoma of the lip: a case report. Journal
of oral sciences 2009;51(3):489491.
- Bandeca MC, Padua
JM, Nadalin MR et al. Oral soft tissue lipomas: A case series. JCDA
June 2007,;73(5):431434.
- Gnepp DR. (Editor)
Diagnostic surgical pathology of the head and neck. WB Saunders; Philadelphia.
2001.
- Weiss SW, Goldblum
JR. (Editors) Benign lipomatous tumors. In: Enzinger and Weisss soft
tissue tumors. 4th ed. Mosby; St. Louis. 2001. pp 571639.
- 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(4):441450.
- Spencer J, Daniels
M. Lipoma of tongue. Saudi dental journal 2006;18(1):1-6.
- 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(1):4953.
- Akyol Mu, Odzzek
A, Sokmensuer C. Lipoma of the tongue. Otolaryngol Head Neck Surg 2000;122:461462.
- Woodhouse JB, Delahunt
B, English SF, Fraser HH, Ferguson MM. Testicular lipomatosis in cowdens
syndrome. Mod Pathol 2005;18(9):11511156.
- Gier Re. Yellow
conditions of the oral cavity. In: Wood NK, Goaz Pw, editors. Differential
diagnosis of oral and maxillofacial lesions, 5th edition.
St. Louis: Mosby year book Inc., 1997. p. 225231.
- Garavaglia J, Gnepp DR. Intramuscular (infiltrating) lipoma of the tongue.
Oral Surg
Oral Med Oral Pathol 1987;63(3):348350.
- Shirasuma K, Saka
M, WAtatani K, Kogo M, Mattuya T. Infiltrating lipoma of the tongue.
Int J Oral Maxillofac Surg 1989;18(2):6869.
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