Tumor Grade Vs. Stage
- Grade
- histologic assessment of how closely a neoplasm resembles the original tissue
- graded I-IV
- score given on degree of differentiation and number of mitoses
- important determinant of prognosis
- the less a tumor resembles the original tissue the worse the prognosis
- Stage
- degree of size and spread of a neoplasm
- typically has more prognostic value than grade
- importance in determining stage
- metastasis (non-lymph node) > lymph node involvement > size of tumor
- importance in determining stage
- TNM staging system is commonly used to describe the stage
- T = size of tumor
- N = node involvement
- M = metastases
- determined after surgical resection of tumor
Tumor nomenclature
- Carcinoma denotes epithelial origin
- Sarcoma denotes mesenchymal origin
| Cell type | Benign | Malignant |
| Epithelium | Adenoma, papilloma | Adenocarcinoma and papillary carcinoma |
| Melanocyte | Nevus | Melanoma |
| Mesenchyme | ||
| Blood cells | n/a | Leukemia and lymphoma |
| Blood vessels | Hemangioma | Angiosarcoma |
| Smooth muscle | Leiomyoma | Leiomyosarcoma |
| Skeletal muscle | Rhabdomyoma | Rhabdomyosarcoma |
| Bone | Osteoma | Osteosarcoma |
| Fat | Lipoma | Liposarcoma |
| >1 cell type | Mature teratoma (women) | Immature teratoma and mature teratoma (men) |
Tumor differences
- Benign
- usually well-differentiated (i.e. low grade)
- slow growing
- well circumscribed
- no metastasis
- Malignant
- may be poorly differentiated (i.e. high grade)
- erratic growth
- poorly circumscribed
- may metastasize