Incomplete paresis of the sciatic nerve due to massive atypical lipoma of the pelvis: a case report

BACKGROUND: Liposarcomas are classified into four subtypes, with different malignancy potential and characteristic imaging appearances. Well-differentiated liposarcomas have imaging characteristics similar to those of benign lipomas, however they can be usually distinguished from lipomas because of the larger size and broader fibrous septa, with a more nodular appearance. CASE PRESENTATION: This paper presents a case of atypical lipoma (well-differentiated liposarcoma) of the pelvis, leading to partial involvement of the sciatic nerve. In our case, computed tomography (CT) showed a low-density lesion. In magnetic resonance imaging (MRI), T1 and T2-weighted sequences revealed a fatty appearance with signal loss on fat saturation pulse sequences. CONCLUSION: The lesion was successfully resected and no other similar lesions have been found within one year of follow-up.