Oral Intramuscular Lipoma with Unusual Clinical Presentation: Differential Diagnosis and Review of the Literature

Lipoma is a soft tissue neoplasm that frequently affects adults but has a low frequency in the oral cavity. Intramuscular lipoma (IML) is a distinctive variant of lipoma, commonly affecting the muscles of the upper extremities. To date, approximately 22 cases of IML affecting the oral cavity have been reported.

Here, we report two oral IML cases showing unusual clinical features. A 30-year-old female was referred for evaluation of a nodular lesion on the mucosal surface of the lower lip, clinically suggesting mucocele. A 48-year-old man presented with a nodular lesion, yellowish coloring, asymptomatic, located at the posterior lateral portion of the tongue, clinically suggesting lymphoepithelial cyst, subgemmal neurogenous plaque and lateral lingual tonsil hypertrophy.

After excisional biopsy, mature adipose tissue permeated by skeletal muscle bundles was observed in both cases, confirming the diagnosis of IML.

Although rare, IML should be included in the differential diagnosis of nodular lesions affecting the oral cavity.