Robotic-Assisted Resection of Transverse Colonic Leiomyosarcoma With Suspected Lymph Node Metastasis.

Colonic leiomyosarcoma is an exceptionally rare gastrointestinal mesenchymal tumor, often misclassified before the advent of immunohistochemical markers distinguishing it from gastrointestinal stromal tumors (GIST). We report the first case of robotic-assisted surgery for a transverse colonic leiomyosarcoma with suspected lymph node metastasis. A 73-year-old male presented with abdominal discomfort. Imaging revealed intussusception due to a 3-cm tumor in the transverse colon and an 8-mm enlarged lymph node. Biopsy showed spindle cell proliferation, immunohistochemically positive for α-SMA and desmin, but negative for GIST markers. Based on these findings, a diagnosis of leiomyosarcoma (cT1N1M0, Stage III) was made. Robotic transverse colectomy with regional lymphadenectomy was performed, achieving complete resection. Pathology confirmed a 3-cm leiomyosarcoma without nodal metastasis. The patient recovered uneventfully and remained disease-free at nine months. Although lymph node metastasis in colonic leiomyosarcoma is uncommon, effective systemic chemotherapy has not been established, and reliable preoperative assessment of nodal involvement remains challenging. Therefore, complete surgical resection remains the only potentially curative treatment, and robotic-assisted surgery may offer significant advantages by facilitating precise and meticulous operative management. To the best of our knowledge, this is the first reported case of robotic-assisted surgery for colonic leiomyosarcoma.