Souza, Dante L. S.

Background: Primary colorectal sarcomatoid carcinoma is a rare and aggressive malignant neoplasm that displays mixed epithelial and mesenchymal differentiation, with uncertain histogenesis. First described in 1986, there is a paucity of literature related to this condition and there are no evidence-based treatment guidelines. The aim of our study is to present our 30-year experience with primary colorectal sarcomatoid carcinoma. Methods: Retrospective single-center analysis of all patients treated for primary colorectal sarcomatoid carcinoma from 1992 to 2022. The primary outcome was response to treatment strategy and overall survival. Results: A total of six cases met eligibility criteria. Three were male (50%) with a mean age at diagnosis of 59 years (range, 49-72). Four neoplasms were located in the rectum (66%) and two in the colon. Mean tumor size at diagnosis was 4.8 cm (range, 2.8-7.0). Three patients were treated endoscopically and three underwent oncologic surgical resection. Five experienced recurrence and one expired from other comorbidities. The mean survival among those with colonic and rectal sarcomatoid carcinoma was 7 months (range, 3-11) and 39 months (range, 9-60), respectively. Discussion: Primary colorectal sarcomatoid carcinoma is a rare malignant tumor with poor prognosis. Treatment modalities have not been standardized and despite multimodal therapy, disease recurrence and/or metastasis is likely to occur. Further studies are necessary to determine optimal treatment to improve outcomes.