Malignant Tumors

1- Osteoclastoma (Giant cell tumor): -large number of multinucleated giant cells ,of the osteoclastic type . The cells contain up to 100 nuclei over cytoplasm or grouped in center,nuclei are small,round .in between the giant cells there are numerous, small ,oval and fusiform cells. - The tumour show areas of degeneration , necrosis and haemorrhage.

2- Osteosarcoma (Gross): - Osteosarcoma is often a large (over 5 cm), metaphysically centered, fleshy or hard tumor which may contain cartilage. It frequently transgresses the cortex and is associated with a soft tissue mass

3- Osteosarcoma (Micro): -undifferentiated parts of the tumour appear as large spindle , round or oval malignant osteoblasts irregularly, multinucleated malignant giant cells are present .differentiated parts show matrix between tumour cells ,osteoid and fibrous. - The tumour show areas of necrosis and haemorrhage

4- Squamous cell Carcinoma, skin: -the dermis shows masses of malignant epithelial cells, variable in size and shape, cytoplasm is abundant and pink, the center cell show complete cornification and form a dark red mass of keratin “cell nest”

5- Basal cell Carcinoma: -the dermis is infiltrated by masses of malignant epithelial cells variable in size and shape,the outer cells are columnar and parallel ,the inner cells are polyhydral and round with no evidence of keratinization or cell nest , cytoplasm is bluish, nuclei are large ,oval.

6- Adenocarcinoma in colon: -submucosa and muscle layer are infiltrated by malignant acini ,vary in size & shape ,it are lined by one or more layers of malignant cells.

7- Mucoid carcinoma in colon: -submucosa and muscle layer are infiltrated by malignant acini ,vary in size & shape ,it are lined by one or more layers of malignant cells,the cells are distended with pale mucin and nucleus become eccentric and flattened(signet ring appearance)

8- Metastatic malignant melanoma in liver: -The tumor has the highly hemorrhagic appearance that is characteristic of this entity.