Most of the organs of the human body are covered by an isolation textile to separate the structures, this coverage is formed by cells epiteliales.

This way there can separate the pipes of conduction of hormones, of digestion or of separation between dense organs. Most of the carcinogenic tumors originate in these coverages called epitheliums or wall epitelial from the organs and for it the malignant degeneration of these structures is what is called an epitelial cancer or carcinoma.

The most frequent of this type are those of the mammary gland in to the woman or the colon in the man, in both cases there are cells epiteliales that they cover and or form the mammary gland or the digestive pipe.

When a few cells epiteliales malignizan in an organ there takes place a carcinoma that is usually of only one organ normally, this way if it is of womb a uterine primary carcinoma will take place, if it is of lung it will be a primary lung carcinoma.
When a carcinoma of this type does not talk each other it expands to other organs and this is what is called metástasis or secondary carcinoma. Not all the carcinomas it has the same aptitude to expand, and for it there are more or less aggressive some of them in this sense.

When a carcinoma has spread to different places and not only there is a primary one and a secondary one but several or secondary many it is when one speaks about carcinomatosis.

If a prostate cancer spreads to adjacent textile and ganglions of the area it is not called carcinomatosis, but if it has spread to lung, bones and brain is when already if we can use the name of carcinomatosis.
This name is used usually to define the extension to different organs of other forms of cancer not definitely of origin epitelial.