A Huge Recurrent Atypical Lipomatous Tumor (Well-Differentiated Liposarcoma) going in to Dedifferentiation 12 years after its First Detection.

Introduction: Soft-tissue sarcoma (STS) being a rare malignancy, many times it undergoes inadequate surgery at first instance, leading to higher chances of recurrence. Atypical lipomatous tumor (ALT)/well-differentiated liposarcoma frequently undergoes first inadequate surgery leading to higher recurrence rate and sometimes getting converted to higher grade malignancy like dedifferentiated liposarcoma. Case Report: We had a 63-year-old female who presented with recurrent huge (dimension on final histopathology report: 29 × 24 × 11 cm) ALT of thigh after three prior surgeries over the span of 8 years. We resected it with wide margins and did a prophylactic nailing at second stage. Final histopathology report came out to be liposarcoma with foci of low-grade dedifferentiation (FNCLCC Grade 3). Patient received post-operative radiotherapy. At final follow-up of 35 months, our patient is recurrence free, doing all her daily routine activity independently. Conclusion: Ten percentages of the ALT dedifferentiate into dedifferentiated liposarcoma, which has 15-20% metastatic potential compared to almost nil in ALT which happened in our case. Due to this, we recommend treatment of ALT and all STS at a tertiary cancer care center by a multidisciplinary team as it requires adjuvant treatment also apart from surgery with adequate margins.