Laparoscopic Abdominoperineal Resection of Undifferentiated Spindle Cell Sarcomas of the Rectum with Lymph Node Metastases: A Rare Case Report.

Introduction: Undifferentiated sarcomas of the gastrointestinal tract are rare and have poor prognoses, especially those with lymph node metastases. There is no consensus on the treatment plan. While there are reports on undifferentiated pleomorphic sarcomas of the rectum, no reports on undifferentiated rectal spindle sarcomas with lymph node metastases have been presented previously.

Case presentation: We report a case of a 97-year-old woman referred to our hospital with anal pain. Imaging findings indicated multiple tumors in the rectum below the peritoneal reflection protruding from the anus and two enlarged pararectal lymph nodes. Laparoscopic abdominoperineal resection of the rectal sarcomas with lymph node metastasis was performed to alleviate the pain with uneventful postoperative courses. The immunostaining did not reveal a trend of tumor cell differentiation. The tumor was diagnosed as undifferentiated spindle cell sarcoma based on histopathological findings. Because of advanced age, the patient is followed up on an outpatient basis without additional postoperative treatment.

Conclusion: The prognosis of undifferentiated sarcomas is poor. While radical resection is the primary treatment, the efficacy of preoperative radiation therapy, cytotoxic chemotherapy, and immune checkpoint inhibitors has been investigated recently. Accumulating cases of this disease is important to determine treatment plans, and this report is valuable in this regard.