Colorectal carcinoma/pathology

Precancerous lessions
Precancerous lessions are considered to be dysplastic adenomas dysplastic adenomas (polyps, tumor) and other intraepithelial neoplasias such DALM (Dysplasia Associated lesions or Masses) in ulcerative colitis. The risk of their malignant reversal is closely related to the degree of dysplasia.

. náhled|350 px| Resekát tlustého střeva, viditelný jeden exofyticky rostoucí karcinom a dva adenomatózní polypy

Macroscopy
Based on the nature of growth, possible complications of the disease can be deduced. In terms of macroscopy, we divide CRCA into three groups:


 * exophytic (polyposis) - the main risk is obstruction of the intestinal lumen ( ileus ) and rarely intestinal invagination;
 * excavated (exulcerated) - the risk is mainly bleeding and perforation of the intestinal wall with subsequent peritonitis ;
 * flat (infiltrating) - may remain clinically silent for a long time.

As annular carcinoma, we mainly call left carcinomas growing around the entire perimeter of the intestine and leading relatively soon to stenoses with all the consequences. On the contrary, right-hand cancers grow mainly exophytically.

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Tumor localization by frequency ======


 * left colon – 64 %;
 * rectum – 30 %;
 * sigmoideum – 26 %;
 * colon descendens – 8 %;
 * colon transversum – 13 %;
 * colon ascendens – 9 %;
 * caecum – 14 %.

Microscopy
náhled|250 px| Histologie: tubulární adenokarcinom, barveno HE

Microscopocally, it is mainly an adenocarcinoma (in 95 % ), then we distinguish their differentation:


 * G1 – well differentiated (tubular or papillary);
 * G2 – moderately differentiated;
 * G3 – low differentiated (solidly arranged) - with worse prognosis.

We also have several rarer types of CRCA - mucinous (mucus-forming) adenocarcinoma (for which, as the name suggests, the formation of extracellular mucus is typical), adenosquamous carcinoma and ring cell carcinoma.

Staging
We commonly use 2 classification systems to classify CRCA


 * TNM classification,
 * Dukes system.


 * Comparison of TNM classification and Dukes system

Metastasis
CRCA metastasizes, like most cancers, primarily lymphogenically - to local lymph nodes. Later to the distant lymph nodes and hematogenously most often to the liver and lungs. Advanced disease can spread after the peritoneum (so-called carcinomatosis of the peritoneum ). Rectal carcinomas tend to grow into the surrounding organs (vagina, uterus, ureter, bladder, but also os sacrum). In women it is typical of metastases in the ovaries. In some cases, the metastatic process and related complications can be detected before the primary tumor itself.

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 * Colorectal carcinoma