Neoplasia Dr. Raid Jastania

Neoplasia: Terminology Cancer is the 2 nd cause of death in the US Neoplasia is “new growth” Neoplasm is an abnormal mass of tissue the growth of which exceeds and is uncoordinated with that of the normal tissues and persists after cessation of stimuli (By Willis)

Neoplasia: Terminology Loss of normal growth (growth autonomy) Loss of normal differentiation Transformation Tumor: swelling, mass of tissue Oncology: Study of tumors Benign vs Malignant –Benign: localized, not fatal –Malignant: cancer, invasive, metastasize, fatal

Neoplasia: concept of origin Zygote – cells – tissues – organs – human DNA, genetic material, genes are the present in all the cells of the body Cells differ in gene expression Type of cells (based on genes expressed) –Control of growth –Differentiation Monoclonality is the basis of neoplasia Tumor progression, divergent differentiation

Nomenclature Benign tumors –Suffix “–oma” is added to the cell type Fibrous: fibroma Cartilage: chondroma Bone: osteoma Adipose tissue: lipoma Smooth muscle: leiomyoma Skeletal muscle: rhabdomyoma Blood vessels: hemangioma Epithelial: adenoma (cystadenoma, papilloma)

Nomenclature Malignant tumors –Mesenchymal: sarcoma Fibrous: fibrosarcoma Cartilage: chondrosarcoma Bone: osteosarcoma Adipose: liposarcoma Smooth muscle: leiomyosarcoma Skeletal muscle: rhabdomyosarcoma Blood vessels: angiosarcoma –Epithelial: carcinoma Gland forming: adenocarcinoma Squamous: Squamous cell carcinoma Transitional cell: Transitional cell carcinoma (urothelial carcinoma)

Nomenclature Mixed tumors: –Pleomorphic adenoma of salivary gland –Fibroadenoma of breast Teratoma: more than one germ-cell layer –Teratoma contains: bone, epithelium, muscle, fat, nerve….

Nomenclature Exceptions: –Malignant tumors Lymphoma, melanoma, mesothelioma, seminoma Hamartoma: not neoplastic, it is rather a malformation. Hamartoma contain mixture of mature (adult-type) tissue in abnormal distribution and arrangement Choristoma: Hetrotopic rest. It is normal tissue in abnormal place.

Benign and Malignant How do we know benign from malignant tumor? Features: –Differentiation and Anaplasia –Rate of Growth –Local Invasion –Metastasis

Differentiation and Anaplasia Differentiation is the extent to which tumor cells resemble their normal cells morphologically and functionally Generally: –Benign tumors are well differntiated –Malignant tumors can be well differentiated, moderately differentiated or poorly differentiated. They can be “undifferentiated” Anaplasia is lack of differentiation

Differentiation and Anaplasia Anaplasia is lack of differentiation –Peomorphism –Hyperchromatic nuclei –High nuclear to cytoplsmic ratio (N/C ratio) –Giant cells –Mitosis –Loss of polarity and normal arrangement –Loss of sturcture

Differentiation and Anaplasia Function: –Benign tumors: have normal function eg. Adrenal cortical adenoma –Malignant tumors: have variable function according to the degree of differentiation eg. Hepatocellular carcinoma produces bile

Differentiation and Anaplasia Dysplasia: –Not neoplstic growth –Disordered growth and differentiation –Show mild anaplastic features eg. Nuclear pleomophism, hyperchromasia, mitosis….

Rate of Growth Benign: slow growing Malignant: fast growing

Relation between Growth and Differentiation

Local Invasion Benign tumors: localized, may be surrounded by pseudocapsule “capsule” Malignant: invasive, infiltrating, destructiv, penetrating

Metastasis Secondary implants discontinuous from the primary tumor –30% of newly diagnosed cancer has metastasis –20% has occult metastasis Modes of metastasis: –1. Seeding in body cavity –2. Lymphtics: lymph nodes –3. Hematogenous: liver, lung, brain….

Benign and Malignant In summary, Features of malignancy are –Less Differentiation and More Anaplasia –Rate of Growth - high –Local Invasion –Metastasis