Biology Quiz: Neoplasia and Tumors

Neoplasia

• Neoplasia means new growth
• The study of tumors is called Oncology
• A neoplasm is a tumor that can be benign or malignant

Hyperplasia vs. Neoplasia

• Hyperplasia: has a useful function, controlled growth, growth stops after removal of stimulus, cells have normal shape and pattern
• Neoplasia: has no useful function, uncontrolled growth, growth doesn't stop after removal of stimulus, cells have abnormal shape and pattern

Grading of Dysplasia

• Grade I: dysplasia affects lower 1/3 of cell thickness
• Grade II: dysplasia affects lower 2/3 of cell thickness
• Grade III: dysplasia affects the entire thickness of cells (carcinoma in situ)

Classification of Neoplasms

• Benign: does not invade surrounding tissue, does not metastasize
• Malignant: invades surrounding tissue, metastasizes
• Locally Malignant: carcinoma in situ, malignant cells involve the entire thickness of the epithelium without penetration of the basement membrane

Benign vs. Malignant

• Benign: usually small, slow rate of growth, capsulated, necrosis and hemorrhage are rare, well-differentiated, suffix: oma (e.g. fibroma)
• Malignant: usually large, fast rate of growth, non-capsulated, necrosis and hemorrhage are common, poorly differentiated, suffix: carcinoma, sarcoma (e.g. squamous cell carcinoma)

Anaplasia

• Always indicates malignancy
• Cells are very poorly differentiated
• Characteristics: pleomorphism, loss of polarity, high rate and abnormal mitosis

Neoplasms Nomenclature

• Benign: adenoma, papilloma, fibroma, osteoma, chondroma, lipoma, leiomyoma, rhabdomyoma
• Malignant: adenocarcinoma, squamous cell carcinoma, fibrosarcoma, osteosarcoma, chondrosarcoma, liposarcoma, leiomyosarcoma, rhabdomyosarcoma

Cell of Origin

• Gland: epithelium
• Lining: epithelium
• Fibroblast: fibroma
• Osteoblast: osteoma
• Chondrocyte: chondroma
• Lipocyte: lipoma
• Smooth muscle: leiomyoma
• Skeletal muscle: rhabdomyoma

Benign Tumors of Epithelial Origin

• Adenoma: benign epithelial neoplasms producing gland pattern
• Papilloma: benign epithelial neoplasms growing on any surface that produce microscopic or macroscopic finger-like pattern
• Transitional cell papilloma: site: transitional epithelium of urinary tract, gross: non-capsulated, with long thin papillae, usually compound and branching, reddish and fragile, microscopic: branched core of vascular CT covered by hyperplastic transitional epithelium
• Breast fibroadenoma: benign neoplasm most commonly diagnosed in younger women of reproductive age

Benign Tumors of Mesenchymal Origin

• From CT: fibroma, lipoma, osteoma, chondroma
• From muscles: leiomyoma, rhabdomyoma
• From vessels: hemangioma, lymphangioma

Lipoma

• Benign neoplasm arising from fat cells
• Characteristics: slow growing, non-invasive, closely resembles the tissue of origin

Fibroma

• Definition: benign tumor of fibrous tissue
• Sites: subcutaneous, submucous fibrous tissue and fibrous stroma of organs
• Gross: round, oval, grayish white, capsulated mass
• Microscopic: bundles of fibroblasts and collagen fibers, fibroblast are fusiform with scanty cytoplasm and spindle nuclei

Chondroma

• Definition: benign tumor of hyaline cartilage
• Site: short bones of hands, feet, and flat bones, sternum, and ends of long bones
• Microscopic: cartilage cells are round with vacuolated cytoplasm and separated by pale blue hyaline matrix

Osteoma

• Definition: benign tumor arising from bone
• Types: compact osteoma, cancellous osteoma

Leiomyoma

• Definition: benign tumor of smooth muscles
• Sites: uterus, esophagus, stomach
• Gross: uncapsulated, gray white mass
• Microscopic: characteristics of smooth muscle cells