It’s a disturbance in growth: Can be : 1- Acquired 2- Congenital Neoplasia: it’s a new growth, purposeless and progressive. May be: Benign or Malignant.

1- Adenoma in colon (Gross): -Colonic adenomas are localized proliferations of dysplastic epithelium which are initially flat, but with increased growth project from the mucosa forming polyps. polyps have a head with a cobblestone or lobulated red-brown surface

2- Adenoma in intestine (Micro): Proliferated glands forming new acini variable in size and shape and lined by columnar cells.

3- pericanalicular fibro adenoma in breast : -Proliferative ducts,rounded or oval. Their lumens are patent. They are lined by two layers of cells, outer flattened and inner cubical. -the ducts separated by fibrous tissue, the tumor is surrounded by fibrous capsule

4- Fibroma: Bundles of fibroblasts and collagen irregular arranged (or concentrically),fibroblasts are separated by pink bundles of collagen. the tumor is surrounded by fibrous capsule

5- Fibromyoma : -Red bundles of muscle tissue alternating with pink bundles of fibrous tissue. -muscle cell is spindle shaped with rod shaped nucleus,the cell are seperated by pink collagen fibers, the tumour has no fibrous capsule.

6- Neurilemmoma( Shwannoma) : -long thin spindle shaped cells with rod shape nuclei arranged in bundles. - The nuclei in each bundle are placed side by side in a palisade manner. - Tumour shows a fibrous capsule and few B.V

7- Benign melanoma in skin: -groups of nevus cells separated by collagen bundles, the nevus cells(melanocytes) are small, round or polyhedral, shows dark brown melanine pigment present in cells, the nevus has no capsule.