Utilidad de la PET/TC-FDG en el diagnóstico y seguimiento del adenocarcinoma mucinoso de colon

Among the various histological subtypes of colorectal cancer, approximately 5% to 20% correspond to mucinous adenocarcinoma (MAC), a malignant variant with poor clinical prognosis, associated with higher metastasis rates, and is often presenting at an advanced stage with multifocal metastatic involvement, in contrast to conventional colorectal adenocarcinoma. Multiple studies suggest that positron emission tomography with fluorodeoxyglucose (FDG-PET) has higher accuracy in staging metastatic or recurrent colorectal adenocarcinoma compared to computed tomography scans (TC). However, the routine application of FDG-PET in clinical practice remains controversial. We report two cases of recurrent or persistent macroscopic tumor with false-negative findings on this complementary imaging study used for follow-up in patients with colon mucinous adenocarcinoma. Despite studies showing FDG-PET to be more sensitive than CT for detecting metastatic or recurrent colorectal cancer, this imaging modality may not be equally effective for detecting metastases and recurrences of mucinous adenocarcinoma due to the hypocellularity of these tumors, resulting in decreased FDG accumulation. As a result, FDG-PET is not considered an effective imaging modality for surveillance in patients with mucinous adenocarcinoma.