부산대학교 도서관

Atypical lipomatous tumor (ALT), one of the histologic subtypes of liposarcoma, is locally aggressive with intermediate malignant potential and is categorized as a synonymous entity with well-differentiated liposarcoma (ALT/WDLPS). Although ALT/WDLPS is the most common subtype of liposarcoma in the oral and maxillofacial region, its occurrence is extremely rare, and asymptomatic clinical behavior often delays definitive diagnosis and treatment. We present an extremely rare case of ALT/WDLPS in the buccal mucosa of an elderly Japanese woman. A provisional diagnosis of benign tumor was made from clinical symptoms that involved findings on magnetic resonance imaging. Microscopic examination revealed mature adipocytes with substantial variation in cell size, fewer multivacuolated lipoblasts, and positive stain with MDM-2 and P16, which resulted in a definitive diagnosis of ALT/WDLPS. Conservative surgical resection resulted in locoregional recurrence; however, no evidence of dedifferentiation was detected, and repeat conservative resection finally allowed the patient to avoid esthetic and functional disorder and to obtain an uneventful clinical prognosis over the long-term follow-up period. We also review previous reports of cases of ALT/WDLPS arising from the cheek/buccal mucosa.