Bilateral Lipomas of the Tongue

Lipoma is the most common benign, soft tissue mesenchymal tumor and is composed of tumorous mature adipocytes. It commonly affects the back and shoulders. However, lipoma is relatively infrequent in the oral cavity, with an incidence are 1-5% of all benign oral lesions. In addition, only ten cases with bilateral lipomas of the tongue (BLT) have been reported to date. We describe an extremely rare case of BLT with a review of the relevant literatures.

A 64-year-old Japanese man presented to our department complaining of painless soft nodules on the bilateral margins of his tongue. The patient had neither dysarthria nor difficulty chewing. His medical history included diabetes, angina pectoris, and duodenal ulcer. Intraoral examination revealed non-tender, well-defined, soft hemispherical nodules on the bilateral margins of his tongue. The maximum diameter of the left nodule was 11 mm and that of the right nodule 5 mm. The masses showed a smooth and yellowish surface, and elastic soft nodules of the tongue. There was no lymphatic node enlargement in the neck. He had no family history of similar tumors. Magnetic resonance imaging failed to delineate the tumor masses because of metal artifacts from full-cast crowns on neighboring teeth. On the basis of these findings, the clinical diagnosis was multiple tongue lipomas. Excision of the left-side tumor was performed under local anesthesia, with a thin rim of soft tissue. The lesion consisted of encapsulated, easily enucleated whitish-yellow nodules. Histopathological examination revealed that lobules of mature adipocytes separated by fibrous septa without cellular atypia. The histopathological diagnosis was lipoma. The patient refused excision of the other lesion because it did not bother him and there was no dysfunction.

Lipomatous lesions occuring in bilateral sides of the tongue include benign symmetric lipomatosis (BSL: Madelung’s disease) and symmetric lipomatosis of the tongue (SLT). BSL is defined the syndrome as the presence of multiple symmetrical fatty accumulation involving the head, neck and upper trunk. On the other hand, SLT involves only the tongue. However, SLT is characterized by invasiveness, and absence of encapsulation of the adipose tissue. The present case was in the tongue only and was encapsulated. Therefore, we classified the lesions as BLT.

 The epidemiology of BLT is unknown. To the best of our knowledge, only 10 cases with bilateral lipomas of the tongue have been reported to date. Lipoma generally occurs in middle-aged patients (40-60 years) and in equal gender distribution. However, our literature review reveals that all 10 patients were male and the mean age was 66.2 (49-82) years. The mean age seems to be higher in BLT than in solitary lipoma. Seven cases were Asian men. BLT seems to be more frequent in Orientals. Eight of BLT patients had underlying diseases such as hypertension, liver dysfunction or diabetes. In general, systemic factors are not considered to participate in lipoma onset. These data suggest that BLT is likely to be more influenced by ethnic group, gender and chronic disease than solitary lipoma.

1. Sang-Hwa Lee, et al. Bilateral asymmetric tongue classic lipomas. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 11: e15-e18.

2. Jinbu Y, et al. Symmetric lipomatosis of the tongue: Report of a case. Oral Med Pathol 2004; 9: 123-126