Rare fibrolipoma of attached gingiva: A case report and review of the literature

Abstract

Lipoma is a rare benign tumor. Fibrolipoma, a variant of lipoma, is relatively uncommon in mouth tissues. Among all benign lesions of oral cavity, the approximate incidence rate of lipoma is 1%–4%, with a prevalence rate of about 0.0002%. Fibrolipoma is an extremely rare subtype of lipoma, especially in the attached gingiva. This subtype accounts for 1.6% of all facial lipomas, with a prevalence rate of 1/5000 adults in the oral and oropharyngeal region. It is diagnosed by histopathologic and immunohistochemistry evaluation and treated by total excision. Due to the adhesion to the surrounding tissues and pseudo‐infiltrating characteristics of this lesion, it can get mistaken with malignant lesions; therefore, a histological examination is mandatory. In this paper, a case of a patient with attached gingiva fibrolipoma treated by surgical excision is reported. This case report is about a 26‐year‐old female patient in Shiraz School of Dentistry with a fibrolipoma of attached gingiva. Because of fibrolipoma's growth tendency, adhesion to the surrounding tissues, and specific histological characteristics, its differential diagnosis with malignant infiltrating tumors is important. Surgical excision is the gold standard for treatment. Accurate differential diagnosis, careful histological examination, and periodic follow‐up are essential.

As oral fibrolipoma is rare, clinical features, differential diagnosis, and management are essential. Our case is an uncommon feature of FL in a rare location (gingiva) that results in misdiagnosis with several lesions like soft tissue tumors. Furthermore, surgical treatment of such lesions, especially in the gingiva, is challenging.

1. INTRODUCTION

Fibrolipoma (FL) is a histological subtype of lipoma that can be identified by a fibrous component that is mixed with adipose tissue lobules. ³ Its consistency depends on the amount and distribution of fibrous tissue and the tumor depth. It may vary from soft to firm. ⁴ The etiopathogeneses of lipoma and fibrolipoma remain unknown, ⁵ 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. ⁶ 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. ⁶ , ⁷ 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. ⁸ A follow‐up must be considered. It can appear in all ages, although it is mostly diagnosed in 40–60 years old patients. ⁹ These lesions have a mean diameter of 2 centimeters (cm) in the oral cavity. ¹⁰

Among all benign oral lesions, oral lipoma has 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 43 cases of intraoral FL till now. ¹ Several reported cases of this condition are shown in Figure 1.

FIGURE 1.

Summary of pervious reported cases of oral fibrolipoma (6)

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.

2. CASE DESCRIPTION AND RESULTS

A 26‐year‐old woman, without any history of drug usage, was referred to Shiraz Oral and Maxillofacial Medicine department from the Periodontal department with a chief complaint of left lower attached gingiva swelling. Written informed consent was obtained from the patient to publish this report in accordance with the journal's patient consent policy. The swelling had first been noticed two years earlier and had subsequently exhibited gradual, continuous enlargement. There was no pain or bleeding. The exophytic lesion was a dome‐shaped base, smooth surface, non‐homogenous color (pale pink‐red and somewhere yellow), homogenous texture, soft in palpation but not fluctuant or mobile on the left lower gingiva next to the first and second mandibular molars (Figure 2). Its total measuring was 1.5 × 1 × 0.7 cm. She had no medical problems and no familial history due to similar lesions. We asked our patient several clinical questions about the lesion's pattern of growth, general pain, bleeding, time of lesion existence, trauma, and fever; as already mentioned, it appeared two years ago and had a gradual enlargement, there was no evidence of pain, bleeding, trauma, or fever. We operated some clinical and paraclinical examinations such as palpation, examination of other parts of her mouth, lymphadenopathy, aspiration, vitality test, probing, and periapical radiography. There was no other lesion in her mouth similar to our studied lesion, the aspiration was negative, teeth adjacent to the lesion were vital and did not have any periodontal problems. Regarding the differential diagnosis, the exophytic lesion could be reactive or tumoral; a reactive lesion was ruled out as there was no trauma or stimulating factor based on the patient's history; also, teeth adjacent to the lesion were vital. Therefore, the lesion could be tumoral: due to its continuous enlargement and lack of any stimulating factor. As its growth progress was slow, the tumoral lesion could be benign and as its consistency was soft, it could be a lipoma, neurofibroma, or pyoderma gangrenosum. For patient management, after signing the written consent form, we did an excisional biopsy and considered a follow‐up. The tumor was excised under local anesthesia (by long buccal anesthesia or anesthetizing all around the lesion, the lesion was removed from its base with a blade); then, the specimen was placed in a formalin solution, and it was sent for a histopathological examination to the Pathology department. In the microscopic examination, sections showed a piece of oral mucosa covered by parakeratotic stratified squamous epithelium. The underlying connective tissue demonstrated abundant collagen fibers intermixed with lobules of fat cells (Figure 3). Therefore, a fibrolipoma was finally diagnosed. Patient was followed up to 3 months after excision, and no recurrency was reported.

FIGURE 2.

Photograph of our case showing an exophytic lesion with a dome‐shaped base, smooth surface, non‐homogenous color (pale pink‐red and somewhere yellow), and homogenous on the left lower gingiva next to the first and second mandibular molars

FIGURE 3.

Microphotograph showing piece of oral mucosa covered by parakeratotic stratified squamous epithelium. The underlying connective tissue demonstrates abundant collagen fibers intermixed with lobules of fat cells. (H & E stain, 40X (upper left figure), 100X (upper right figure), and 200X (lower left figure) magnification)

3. DISCUSSION

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).

As an example, FL's 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. The lesion of our patient is located in the gingiva and is in differential diagnosis with reactive lesions; therefore, its clinical diagnosis is more difficult. Moreover, its treatment (surgical procedure) can cause a gingival recession and esthetic problems in the gingiva for the patient; thus, the surgical procedure is challenging and must be done with extreme attention. The lesion of our patient was excised, and the patient was followed; no periodontal or esthetical issue was observed.

Lipomas and FL 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 depend 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. We reviewed 6 cases as described in Table 1. They aged from 25 to 75 years, and 50% of them, similar to our case, were females.

TABLE 1.

Reviewed cases of FL in the English literature

Author	Age a /Sex	Site of the lesion	Size b	Characteristics	Symptoms	Consistency
Castellani et al. 2015 14	25/ F	Intraosseous of right mandibular ramus	–	radiolucency in the right mandibular ramus in the OPG radiograph	None	–
Iaconetta et al. 2015 13	71/ F	Ventral surface of the tongue	40	curvy shaped‐ movable‐ covered by mucosa	dysfunction of phonation and swallowing, and a sensation of ‘obstruction’ of the oral cavity	Soft
Manjuanatha et al. 2010 6	75/ M	Right buccal mucosa	30	Pedunculated	None	Soft
Manjuanatha et al. 2010 6	55/ M	Right buccal mucosa	10	Sessile	None	Firm
Manjuanatha et al. 2010 6	70/ M	Soft palate	15	Sessile	None	Soft
Kiehl 1980 15	65/ F	Beneath a mandibular complete denture	15	Freely movable‐ yellow‐ encapsulated‐ covered by thin epithelium	None	Soft

Abbreviations: F, female; M, male; OPG, Orthopantomography.

^a Age: in years.

^b Size: in millimeters.

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 Iaconettas, 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

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. 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 examination is necessary to clarify the nature of the neoformation and to resolve any doubt. ⁸ 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.

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 which are presented in Figure 1 and Table 1.

Our study limitations included lack of genetic evaluation and short follow‐up duration.

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.

AUTHOR CONTRIBUTIONS

Not applicable.

CONFLICT OF INTEREST

The authors have no conflicts of interest to declare that are relevant to the content of this article.

CONSENT

Written informed consent was obtained from the patient to publish this report in accordance with the journal's patient consent policy.

Rezazadeh F, Jaafari‐Ashkavandi Z, Afshari A, Tarjan A. Rare fibrolipoma of attached gingiva: A case report and review of the literature. Clin Case Rep. 2022;10:e06643. doi: 10.1002/ccr3.6643

DATA AVAILABILITY STATEMENT

Not applicable.