Ⅰ.Introduction
Lipoma is a benign soft tissue tumor of mature adipocytes, and about 20% occurs in the head and neck area. But, oral lipomas comprise of only 1% to 4% of cases.
Fibrolipoma is a rare histological variant of lipoma, which is characterized by a significant collagen fibers intermixed with neoplastic fat cells1).
Despite it is benign, when it becomes bigger enough, it can cause discomfort to the patients.
Ⅱ.Case Report
A 28-year-old systemically healthy male patient visited our dental clinic with soft growth on the right hard palate, which has been growing over the past 1 year, causing discomfort on the tongue. There was a solitary painless, well-defined, pedunculated, semi-firm and pale pinkish mass, measuring 1.3x1.0x0.8cm on the palatal side of maxillary first premolar. He had not symptoms on any teeth, but there was suspicious bone resorption on palatal area of the maxillary first premolar on CT images. The clinical diagnosis was a fibroma.
Under local anaesthesia, the lesion was excised and the tissue was sent for histopathological examination. The histological examination revealed spindle cell proliferation with mature adipose tissue in collagenous stroma. Overlying sqamous epithelium was intact. And S-100 protein test was negative.
Correlating with the clinical and histopathological examination, the excised lesion was diagnosed as a fibrolipoma. And the postoperative course was uneventful.Fig. 1Fig. 2Fig. 3Fig. 4
Ⅲ.DISCUSSION
Fibrolipoma is a benign soft tissue tumor that rarely occurs in the oral and maxillofacial region, and is classified as a variant of conventional lipoma by the WHO2). This can occur due to fatty degeneration of fibromas and also due to lipogenesis of fibroblasts. It may also arise by preadipocyte differentiation and proliferation mediated by cytokines following soft tissue damage when blunt trauma and hematoma formation occurs3). In present case, apical inflammation of maxillary first premolar may be the cause of the lesion.
Lipomas are benign soft tissue neoplasms of adipose tissue origin and are relatively uncommon in the oral cavity, representing about 1% to 5% of all benign oral lesions4).
Because this neoplasm shows painless, slow-growing features, patients visit the clinician only when it makes functional or esthetic problems. This makes it difficult to measure the actual incidence.
Lipomas are freely mobile in relation to the surrounding tissues and may clinically have a semi-lucent yellow color because of the thin overlying epithelium. The consistency of this lesion varies from soft to firm5). In some cases, fluctuation can be sensed.
We diagnosed fibrolipoma based on the presence of mature adipose tissue interspersed by bands of broad or fascicles of dense connective tissue fibers.
Lipoma and fibrolipoma both are usually well circumscribed and have a thin capsule. Fibrolipoma differs from the classic variant because the mature adipose tissue is interspersed by bands of connective tissue. Studies on lipomas showed variable ratios of fibrolipomas microscopically6,7,8). This could be due to different diagnostic criteria.
The proliferative activity of fibrolipoma revealed greater than other simple variants4). And oral liposarcoma is very rare, but this entity cannot be distinguished from its benign counterpart at clinical examination9). Therefore, accurate histological examination is mandatory, and the differential diagnosis is based on the detection of a lack of lobular architecture, areas of prominent fibrosis and, most importantly, on the presence of multivacuolated adipose cells with indented nuclei.
There are lesions look similar clinically, but they may present diverse histopathological features. So, the authors recommend that histopathological examination of excised tissue. Correct diagnosis plays a significant role in providing successful treatment and preventing malignant transformation.
Complete resection of the lesion should be emphasized, which is the key to avoid recurrence.
It is essential for new cases to be documented so that better treatment modalities could be drawn.
Ⅳ.CONCLUSION
Fibrolipoma is very rare but shows an increased growth potential compared with the classic lipoma. The clinical course is usually asymptomatic until they attain larger size. Differentiation of this lesion with liposarcoma is essential. It is important for new cases to be documented, especially for the rare entities, so we add to the few existing cases of oral fibrolipoma.
