Giant Pleomorphic Lipoma With Malignant Transformation in the Buttock: a Rare Case Report and Literature Review

Abstract

Background: Pleomorphic lipoma is a benign tumor, which is often located in the neck, shoulder, and other subcutaneous tissues. Pleomorphic lipoma with malignant transformation in the buttock is rarely reported.Case Presentation: A 53-year-old male attended to our department with a large mass in his buttock that had been present for about one year, leading to difficulty with walking and defecation. Computed tomography (CT) showed a 10. 2 × 8. 3 cm mass with lumpy and mixed low to medium density shadows in the right side of the lower part of the tailbone. Color Doppler ultrasound showed that the skin and subcutaneous tissues of the right buttock were thickened with lymphedema. Pre-operative pathology revealed a large amount of adipose and fusiform fibrous tissues with obvious blood vessels. The patient underwent complete resection of the mass in the right buttock. Postoperative pathology indicated that the tumor was pleomorphic lipoma with malignant transformation. The patient recovered well and was discharged from the hospital at day 12 post-surgery. Follow up at 6 months did not find any symptoms of tumor recurrence.Conclusions: Pleomorphic lipoma with malignant transformation is rare. CT, magnetic resonance imaging (MRI) and histopathology are the main methods used to diagnose pleomorphic lipoma. Complete resection of the tumor is vital to treat giant pleomorphic lipoma successfully.