Radiation-Induced Liposarcoma of the Groin in a Patient with Prior Vulvar Cancer: A Case Report and Literature Review

Radiation-induced sarcomas (RIS) are rare but severe long-term complications of radiotherapy (RT). They typically arise years after exposure to ionizing radiation used to treat primary malignancies and complicate patient outcomes. Determining the risk associated with these radiation-induced cancers is challenging due to confounding factors such as lifestyle and genetic predisposition. Liposarcomas, which are the most common type of soft tissue sarcomas, originate from adipose tissue and can develop as a late complication of RT. Although they account for a significant portion of soft tissue sarcomas, radiation-induced liposarcomas are still considered rare, making them a noteworthy diagnostic and therapeutic concern. In this report, we present a rare case of radiation-induced dedifferentiated liposarcoma arising 12 years after RT for vulvar cancer. The patient presented with a mass in the groin, which was initially suspected to be a local recurrence. Imaging studies revealed a suspicious lesion on PET/CT, while MRI showed no significant findings. Histopathological evaluation confirmed the diagnosis of dedifferentiated liposarcoma. Surgical resection was performed with a focus on achieving negative margins. A literature review identified nine similar cases, with five being pleomorphic liposarcomas. The average time to presentation was 15 years (interval 3 - 47 years), with a mean radiation dose of 62 Gy. This case highlights the importance of long-term follow-up for cancer survivors and the need for vigilance in diagnosing secondary malignancies following RT.