Medullary colon carcinoma in a patient with serrated polyposis: an extremely rare association

We present the case of a 55-year-old woman with no relevant medical history diagnosed with serrated polyposis following a screening colonoscopy in 2021. In March 2024, a suspicious polypoid lesion was identified in the hepatic flexure. Histological analysis confirmed a poorly differentiated adenocarcinoma. After neoadjuvant chemotherapy, a subtotal colectomy was performed, and the surgical specimen revealed a medullary colon carcinoma, a very rare subtype of adenocarcinoma. The patient is currently disease-free and undergoes colonoscopies every six months. This case highlights the importance of endoscopic follow-up in serrated polyposis and, to our knowledge, this would be the first documented case of medullary carcinoma in a patient with serrated polyposis.