Silent Yet Striking: Medullary Carcinoma Behind an Intestinal Obstruction

Carcinoma of the ascending colon, especially the medullary type, is a rare and poorly differentiated form of colorectal cancer. This case report details a case of a 75-year-old woman with a background of cardiovascular issues, hypertension, and dementia who presented with complete large bowel obstruction and was found to have poorly differentiated carcinoma of the ascending colon with medullary features. The surgical approach involved an exploratory laparotomy followed by a right hemicolectomy. The pathological analysis confirmed a pT3N0M0, G3 stage II tumor, characterized by a loss of MLH1 and PMS2 protein expression, indicating microsatellite instability (MSI-H). Since there was no nodal involvement, adjuvant chemotherapy wasn't deemed necessary. The patient was encouraged to keep up with regular follow-ups, which would include monitoring carcinoembryonic antigen (CEA) levels, a complete metabolic panel (CMP), a complete blood count (CBC), and CT imaging every six months and annually. Although CEA is the most established tumor marker in colorectal cancer, it is still part of the follow-up plan, owing to its lack of sensitivity in the medullary subtype. In addition to this, the recommendation was for a surveillance colonoscopy every three years. This report sheds light on the case's pathological, clinical, and follow-up elements, emphasizing the need for personalized patient management.