Introduction
Although lipoma (a benign soft tissue neoplasm) is common generally, it
has a very low rate of incidence in the oral and pharyngeal region.
Lipoma has numbers of variants: angio-lipoma, fibrolipoma,
chondrolipoma, osteolipoma/chondrolipoma, adenolipoma, perineural
lipoma, and myxoid lipoma [1,2]. Fibrolipoma (FL) is a histological
subtype of lipoma that can be identified by a fibrous component that is
mixed with adipose tissue lobules. Its consistency depends on the amount
and distribution of fibrous tissue and the tumor depth. It may vary from
soft to firm. The etiopathogeneses of lipoma and fibrolipoma remain
unknown, but there are three possible reasons for the appearance of
these lesions: it can be a congenital lesion due to the lack of
endocrinal balance, which can arise with degeneration of a fibromatous
tumor, or maturation of lipoblastomatosis. Moreover, mild trauma may
cause adipose tissue proliferation; also, fibrolipoma can form beneath a
complete denture. Magnetic resonance imaging (MRI) may be useful to
diagnose the types of oral cavity lesions that are raised from adipose
tissue. In general, lipoma displays high signal intensity and appears to
be well-encapsulated masses on both T1- and T2-weighted images.
Immunohistochemically can help to diagnose fibrolipoma by evaluating the
expression rate of proliferating cell nuclear antigen (PCNA) and Ki-67.
The expression of Ki-67 expression may indicate malignancy or
recurrence. Fibrolipoma can show higher Ki-67 expression than classical
lipoma and other variants of lipoma. Surgical excision must be operated
to treat fibrolipoma. The prognosis of this type of lesion is generally
favorable; if the surgery is performed well, it is not likely for this
lesion to return. A follow-up must be considered. It can appear in all
ages; although, it is mostly diagnosed in 40-60 years old patients.
These lesions have a mean diameter of 2 centimeters (cm) in the oral
cavity.
The lipoma of the mouth was described by Roux in 1848 as “yellow
epulis” firstly. Among all benign oral lesions, oral lipoma has an
incidence rate of about 1–4% and a prevalence rate of approximately
0.0002%. The review of English literature demonstrated a variable
distribution of oral lipomas; however, about 50% of them were on the
buccal mucosa. Other 50% of the oral lipomas were diagnosed in the
tongue, floor of the mouth, lips, palate, and gingiva [1,2]. FL is a
highly uncommon variation of lipoma and contains about 1.6% of all
facial lipomas [3]. FL of the oral cavity has been infrequently
reported. To the best of our knowledge, the review of the literature
revealed a total of 33 cases of intraoral FL till now (Figure 1)
[4].
As this lesion does not have any pain and grows slowly in the oral
cavity, it is hard to clinically evaluate its true incidence rate.
Patients report the lesion to the dentist only when it turns
symptomatic, for esthetics, or oral function.
Different studies were explaining their cases due to their rarity:
Pereira reported a rare histologic variant of FL on the lingual marginal
gingiva of the mandibular left third molar of a 35-year-old female
patient in 2014 in India. Iaconetta also reported a rare FL of the
tongue on the ventral surface of the tongue of a 71-year-old female
patient in 2015 in Italy. Furthermore, Castellani reported a rare case
of intraosseous fibrolipoma of the mandible in a 25-year-old female
patient in 2015 in Italy. All these three cases were important to be
reported because of the rareness of FL in the oral cavity and the site
of FL in each of these presented cases.
As mentioned above, FL in the oral cavity is a rare case. In this paper,
a case of gingival FL will be analyzed and its clinic and pathological
features along with the patient management and follow-up will be
discussed.