Accidental Ultrasound Finding of a Giant Intermuscular Gluteal Lipoma with Intrapelvic Extension: A Case Report

Lipomas represent the most common benign mesenchymal tumor. They are usually located subcutaneously and rarely become symptomatic. Occasionally pressure symptoms on adjacent neurovascular structures may be exerted, thereby causing functional impairment. Lipomas rarely grow larger than 5 cm, becoming the so-called giant lipomas, posing a real diagnostic and surgical challenge. We report an unusual case of a 43-year-old Caucasian female with an accidental pelvic ultrasound finding of a giant mass, which was also palpable over the right gluteal region. Interestingly the patient was free of any sciatic nerve compression symptoms. Magnetic resonance imaging (MRI) revealed a soft tissue tumor, partially located in between the external rotator muscles of the hip and the gluteus muscle. The tumor forced up and advanced through the great sciatic foramen into the pelvis. The patient underwent an uneventful complete and safe surgical excision of the gluteal mass, via a wide transgluteal approach. Pathology confirmed lipoma diagnosis. Patient is free from recurrence two years post operatively. Physicians involved in the diagnosis and treatment of gluteal masses should always consider in their differential diagnosis the presence of a sciatic hernia.