Clinical and Pathological Characteristics of Mucinous Adenocarcinoma in Colon Cancer: Comparison with Classic Adenocarcinoma

Abstract Background Mucinous adenocarcinoma of the colon (≥ 50% extracellular mucin) is often regarded as biologically distinct from classic (non-mucinous) adenocarcinoma. We compared their clinicopathological profiles in a contemporary surgical series. Methods We retrospectively reviewed patients undergoing oncological resection for colon adenocarcinoma between October 2021 and March 2026. Rectal tumours, neoadjuvant-treated cases and signet ring cell carcinoma were excluded. Groups were compared with Mann–Whitney U and chi-square or Fisher’s exact tests. Multivariable logistic regression assessed whether mucinous histology independently predicted advanced invasion (pT3–T4) and nodal metastasis (pN+), adjusting for age, sex and tumour laterality (and pT stage in the nodal model). Results The cohort included 155 colon cancers: 29 mucinous (18.7%) and 126 classic. Median age was 76 versus 70 years, and sex distribution was similar. Mucinous tumours were more often right-sided (75.9% vs 44.4%; OR 3.93, 95% CI 1.57–9.86; p = 0.002). Advanced pT stage was common and comparable (86.2% vs 82.5%; p = 0.786). Nodal metastasis was less frequent in mucinous cancers, although this difference did not reach statistical significance (31.0% vs 50.8%; OR 0.44, 95% CI 0.18–1.03; p  = 0.055). TNM stage distribution differed overall ( p  = 0.014), with stage II more frequent in mucinous disease. Poor differentiation was markedly more common in mucinous tumours (24.1% vs 4.8%; OR 6.36; p  = 0.003), whereas lymphovascular invasion was less frequent (10.3% vs 32.5%; OR 0.24; p  = 0.017). In adjusted analyses, mucinous histology was not independently associated with pT3–T4 (aOR 1.40; p  = 0.578) or pN+ (aOR 0.50; p  = 0.132); pT3–T4 predicted nodal metastasis (aOR 3.84; p  = 0.009). Conclusions In this colon-only cohort, mucinous cancers clustered on the right and were more often poorly differentiated, yet were not independently associated with deeper invasion or nodal spread after adjustment. Treating mucinous histology as a distinct subtype may add nuance to pathological risk assessment.