Colorectal carcinoma is a major cause of
cancer associated with a high rate of morbidity and mortality in the western world. One of the pathologic features considered to be important for prognostic is
mucin production. Many authors confirmed that colon
carcinomas with high
mucin content tend to re-occur locally and carry a poor prognosis. For histochemical evaluation of
mucin content, we investigated 149 patients who underwent surgical resection of sporadic
colon adenocarcinomas, all over a 5-year period. For histological classification we used the WHO recommendation (2000) and to be more accurate we sub-classified
mucinous adenocarcinomas by morphometrical analysis in three categories: pure mucinous, with extracellular
mucin more than 80% of the tumoral volume; mixed type, with 50-80% extracellular
mucin; and mixed type with less than 50% extracellular
mucin. For histochemical investigation, we used stains such as:
mucicarmine, PAS ÷
Alcian Blue and High
Iron Diamine ÷
Alcian Blue. Our study proved the predominance of mixed
mucinous adenocarcinomas with less than 50% extracellular
mucin, followed by the pure mucinous type. From the biochemical composition's point of view, the predominant cases were those with acidic
mucins, especially in pure
mucinous adenocarcinomas (>90%), while those with mixtures of acidic and neutral
mucins were present in 62% of the cases. In addition, our study showed the prevalence of
sialomucins over
sulphomucins (68%), particularly in pure
mucinous adenocarcinomas (77%). Clinical pure mucinous forms were detected mainly in advanced stages, but in terms of
lymph node metastasis rate, they were secondary after mixed type with 50-80% extracellular
mucin.