Total laparoscopic R0 resection of a large retroperitoneal leiomyosarcoma HARBORING a rare TP53 mutation: a case report.

Primary retroperitoneal sarcomas (RPS) are rare, with leiomyosarcoma (LMS) being the second most common subtype. While open surgery is the standard of care, total laparoscopic resection for large RPS remains technically challenging and infrequently reported. Herein, we present a rare case of a 60-year-old woman who presented with a 6-month history of dull abdominal pain. Computed tomography revealed a large 10 cm retroperitoneal mass initially mimicking a duodenal gastrointestinal stromal tumour. The patient underwent a successful totally laparoscopic en bloc R0 resection with uneventful recovery. Histopathology and immunohistochemistry confirmed LMS (Actin and Desmin positive; CD117, CD34, DOG1, β-catenin, and S100 negative). Genetic analysis identified a rare TP53 G105R mutation (c.313G > C). Conclusion: Total laparoscopic R0 resection is a safe and feasible option for large LMS when performed by experienced surgical teams. Identifying rare molecular profiles provides deeper insights into the biological behaviour and personalized management of this rare disease.