<unk>  <unk>  is an early form of carcinoma defined by the absence of invasion of surrounding<unk> sues. In other words, the neoplastic cells proliferate in their normal habitat, hence the name 'in<unk> ' (Latin for 'in its place'). For example,<unk>  of the skin, also called Bowen's disease is the accumulation of neoplastic epidermal cells within the epidermis only.
For this reason,<unk>  will usually not form a tumor. Rather, the lesion is flat (in the skin, cervix, etc) or follows the existing architecture of the organ (in the breast, lung, etc). Some<unk> , however, form tumors, for example colon polyps or papillary cancer of the bladder.
Many forms of cancer originate from a<unk> ' <unk>  lesion. Therefore,<unk>  is considered a precursor that may, if left untreated long enough, transform into a more malignant form of neoplasm, invasive carcinoma or, in common language, "cancer".
Many doctors will not refer to<unk> ' as "cancer" when explaining a laboratory report to a patient. However, because most forms of<unk>  have a real potential to turn into invasive carcinoma,<unk>  is usually treated much the same way as a malignant tumor.
In the TNM classification,<unk>  is indicated as<unk> N0M0 (Stage 0).
Carcinoma in situ
Acinic cell carcinoma
Extramammary Paget's disease
Inverted papilloma
Verrucous carcinoma
Intraductal papilloma
Carcinomatosis
Adenomyomatosis