malignant tumors-micro

Tumor Overview

Definition: A tumor (or neoplasm) is an abnormal tissue growth that persists even after the removal of its cause.Oncology: The medical field dedicated to studying tumors.

Types of Tumors

1. Benign Tumors

Characteristics: Localized and typically surgically removable, indicated by the suffix “-oma” (e.g., lipoma, leiomyoma).

2. Malignant Tumors

Definition: Commonly known as cancer.

  • Types:

    • Carcinomas: Malignant epithelial tumors.

    • Sarcomas: Malignant mesenchymal tumors.

    • Lymphomas: Originating from lymphoid tissue.

    • Semi-Malignant Tumors: Some may have a five-year survival rate.

3. Neoplasia

Definition: New growth reflecting clinical behavior.

Tumor Components

1. Parenchyma

Description: Neoplastic cells that dictate the tumor's biological behavior.

2. Stroma

Description: Supportive tissue consisting of blood vessels, connective tissues, and inflammatory cells.

Tumor Nomenclature

Connective Tissue

  • Benign: Fibroma, Lipoma, Chondroma, Osteoma

  • Malignant: Fibrosarcoma, Liposarcoma, Chondrosarcoma, Osteogenic sarcoma

Blood Vessels

Hemangioma vs. Angiosarcoma.

Muscle

Leiomyoma vs. Leiomyosarcoma.

Epithelial Tumors

Adenoma vs. Adenocarcinoma, Papilloma vs. Papillary carcinomas.

Mixed Tumors

Derived from one germ layer.

Benign vs. Malignant Tumors

1. Benign Tumors

Growth Characteristics: Well-circumscribed, slow, no metastases, often mobile.Histological Appearance: Mature tissue, homogeneous cells, rare mitoses.

2. Malignant Tumors

Growth Characteristics: Poorly defined, rapid, frequent metastases, immobile.Histological Appearance: Immature tissue; pleomorphic, atypical mitoses.

Epithelial Tumors

1. Benign Epithelial Tumors

Examples: Basal cell carcinoma (BCC), Squamous cell papilloma.

2. Malignant Epithelial Tumors (Carcinomas)

Examples: Basal cell carcinoma, Squamous cell carcinoma, Adenocarcinoma.Risk Factors: Include immunosuppression, UV exposure, smoking, chronic ulcers.

Tumor Characteristics Comparison

Benign vs. Malignant

  • Benign: Slow-growing, well-demarcated, non-invasive, rarely ulcerated.

  • Malignant: Rapid growth, poorly defined, often invasive with necrosis and hemorrhage.

Carcinoma Staging and Grading

1. Pathologic Staging (pTNM)

T: Depth of infiltration; N: Lymph nodes with metastases; M: Distant metastases.

2. Grading System

Differentiation from well to poorly differentiated based on visible structures.