Abstract Background Gastrointestinal malignancy is a common cause of iron deficiency and occult gastrointestinal bleeding among adults in developed countries. Given the high prevalence of colorectal cancer and adenomatous polyps in our population, it is imperative that these patients undergo early colonoscopy. Sarcomatoid carcinoma (SCA) of the colon is a very rare condition, with less than 30 cases reported in the literature. Given the highly aggressive nature of this neoplasm, it is important to familiarize oneself with its presentation, histopathology and treatment options. Aims Describe a case of SCA of the colon in a cirrhotic patient, presenting initially as iron deficiency anemia of unknown etiology. Methods Case report and literature review. Results A 69-year-old female presented to the emergency department with complaints of progressive weakness and failure to thrive. Past medical history was significant for chronic kidney disease, NASH cirrhosis Child-Pugh C and recurrent hepatocellular carcinoma despite previous radiofrequency ablation. Investigations demonstrated de novo iron deficiency anemia with the following blood results: hemoglobin of 96, iron of 8.6, iron saturation of 20% and ferritin of 56. Subsequently, gastroenterology was consulted in order to assess for an occult source of bleeding. A gastroscopy was first performed in which no abnormalities were found. She then underwent a colonoscopy, which demonstrated a very large indurated nodular ulcer in the ascending colon, suggestive of invasive neoplasm (Figure A). Indeed, the biopsies demonstrated a malignant spindle cell neoplasm consistent with SCA. On immunohistochemistry, the tumor cells stained positive for keratin AE1/AE3, weakly positive for SMA and S-100, but negative for SMM, HMB45, DOG1, C-KIT and CD31. Given her severe comorbidities, no therapeutic options were available for this patient, thus further staging investigations were not pursued. Unfortunately, the patient rapidly deteriorated and died less than 8 weeks following her diagnosis. Conclusions Sarcomatoid carcinoma of the colon is an extremely rare neoplasm with very poor prognosis. Histologically, this tumor is characterized by a typical biphasic pattern, composed of both mesenchymal and epithelial cells. However, as demonstrated in this case, some SCA display a rather predominantly mesenchymal pattern, rendering the diagnosis difficult using morphology only. Immunostaining is therefore used to identify carcinoma features and to rule out similar tumors such as sarcoma, GIST, mesothelioma and melanoma. SCA of the colon is exceedingly aggressive, with remarkably rapid tumor growth and early distant metastasis. Indeed, median survival is reported to be less than 6 months. Given its rarity, no well-defined treatment guidelines exist, however most patients are managed with early radical surgery, adjuvant chemotherapy and close follow-up. Funding Agencies None