Systemic oncologic treatment of metastatic colorectal carcinoma is currently based on chemotherapy in combination with targeted therapy based on the presence of activating mutations in the EGFR-RAS-RAF pathway, regardless of the histological subgroup of the tumor. In this case report, we describe a patient with a mucinous variant of colorectal carcinoma who responded very well to trifluridine/tipiracil in the third-line treatment.
We briefly review the basic features of this histologic subtype, which accounts for 5-15% of all cases, is characterized by high extracellular mucin production, and is associated with a poorer prognosis related to a lower response to chemotherapy. We also point to the early occurrence of neutropenia as a potential predictive marker in trifluridine/tipiracil treatment.