Discussion
Lipomas are the most common benign tumors in almost all parts of the
body that contain adipose tissue. They are relatively uncommon in the
oral cavity (1-5% of all benign lesions in the mouth). Lipomas can be
seen in different parts of the oral cavity. The literature review showed
that half of the oral lipomas were related to the buccal mucosa, and the
other half were found in the lips, tongue, floor of the mouth, palate,
and gingiva. Oral lipomas were seen in all groups of age, but it has
been most frequently reported after 40 years of age [5].
According to their histology, the WHO classifies lipomas in several
groups: conventional lipomas, fibrolipomas, angiolipomas, pleomorphic
lipomas/spindle cells, mixolipomas, condrolipomas, osteolipomas,
miolipomas, lipomatosis, lipomatosis of the nerve, lipoblastomas, and
hybernomas. Other variants of lipomas than conventional lipoma is rare.
As an example, FL, an uncommon variant of lipoma, is particularly rare
in the oral cavity (a prevalence rate of only 1/5000 adults in the oral
and oropharyngeal region). Its difference from conventional lipoma is in
the way that the mature adipose tissue is interspersed by connective
tissue bands [6]. FL has been reported to occur in the buccal
mucosa, buccal vestibule, and tongue more frequently [7,8]. The
reason for reporting our case is the rareness of the fibrolipoma in the
mouth, especially in the gingival part of the oral cavity, and the
importance of its differential diagnosis.
Lipomas are painless and freely mobile. Because of their thin overlying
epithelium, they usually grow at a low rate and can be clinically seen
in a semi-lucent yellow color; the presence and degree of the yellow hue
depends on the degree and depth of fibrosis. Its consistency varies from
soft to firm. This varies because of the depth of the tumor and the
distribution and amount of fibrous tissue. Several cases have shown some
grades of fluctuation as well. Lipoma and FL both usually have a thin
capsule [9].
Regarding histology, FL consists of mature fat cells, which are divided
into lobules by fibrous shoots. This lesion is generally oval-shaped
[8].
Several cases of FL have been reported until this day (Figure 2). We
reviewed 6 cases as described in Table 1. They aged from 25-75 years,
and 50% of them, similar to our case, were females.
In common with Iaconetta, Kiehl, and Manjuantha, the lesion of our
patient was yellow, capsulated, and movable. Its consistency, other than
one case of Manjuantha, which was firm, was similar to our reviewed
cases: soft.
In contrast to the other cases present in the literature described by
Iaconetta, Kiehl, and Manjuantha, the FL of our patient did not show any
mobility. Unlike our case, which was colored pink-red, the lesions
described by Iaconetta and Kiehl were yellow.
The size of the lesions of the cases we reviewed was from 1 to 4 cm;
similarly, the lesion of our patient measured 1.5 cm. Like Kiehl and
Iaconetta’s, our case did not show any pain.
For the management of our patient and all cases we reviewed (Castellani,
Iconetta, Kiehl, Manjuantha), the lesions were removed under local
anesthesia and sent to the Pathology department for further study about
their microscopic characteristics [4,8,10,11].
As already mentioned, lipoma is one of the most common benign tumors in
the body. Lipoma (specifically FL) is extremely rare in the oral cavity.
This exophytic lesion can also be mistaken with reactive or other
tumoral lesions: due to its adhesion to the surrounding tissues and
pseudo-infiltrating characteristics of this lesion because of the
abundance of collagen and connective tissue, it can cause doubts of
differential diagnosis with malignant infiltrating lesions [11,12].
As a result of the lesion’s adherence to the structures that surround it
and its pseudo-infiltrating characteristics, a histological exam is
necessary to clarify the nature of the neoformation and to resolve any
doubt [13]. Therefore, it is mandatory to perform a biopsy and
differential diagnosis and eventually diagnose FL carefully. Another
importance of diagnosing FL is that this lesion is one kind of tumor; as
a result, it has an increased growth potential. FL almost always grows
slowly, but diagnosing it soon and performing the necessary management
is essential for a better prognosis and patient’s comfort. The treatment
for this kind of lipoma in the oral cavity is a surgical incision under
local anesthesia. Although commonly a good result can be observed after
surgery, follow-up must be performed once in several months (depending
on the lesion and patient’s condition) due to its low recurrence rate.
Our study limitations included lack of genetic evaluation and short
follow-up duration.
To diagnose accurately, clinical features and microscopic (histological)
findings must be considered. FL is a rare benign tumor in the oral
cavity with an increased growth potential compared to classical lipoma.
It has a low chance of recurrence.
Lesions that look clinically similar to each other may demonstrate
different and similar histopathological characteristics; they,
therefore, can raise a diagnostic dilemma for a general dentist.
Surgical excision may be an elective treatment for FL, but the
examination of excised tissue along with consultation with an Oral
Pathologist for an accurate diagnosis and careful follow-up is mandatory
to provide a successful treatment and prevent any malignant
transformation.
Our case adds to the few cases of gingival FL which have been reported
in the English literature.
It is essential to document new cases of FL in the English literature so
that better and more accurate treatments can be introduced to prevent
any malignancy and further damage they may cause.