Pathology Quiz: Neoplasia and Dysplasia Concepts

Lab Skills: Pathology of Neoplasia

• Unit 1, Problem 10: Breaking Boundaries
• The course covers lab skills in pathology related to neoplasia.
• Includes information on benign and malignant neoplasms.

Specific Learning Objectives (SLOs)

• Define terms like hypertrophy, atrophy, hyperplasia, metaplasia, dysplasia, and neoplasia.
• Correlate nomenclature of benign and malignant neoplasms with their tissue of origin.
• Differentiate benign and malignant neoplasms.
• Explain grading and staging methods for malignant neoplasms.

Neoplasia

• Neoplasia is abnormal cell growth.
• Tumors come from abnormal cell growth.
• Normal skin cell growth = cell cycle.

Disorders of Cell Growth

• Non-Neoplastic: Hypertrophy, atrophy, hyperplasia, metaplasia, and dysplasia.
  • Reversible changes
• Neoplastic (tumors): Benign and malignant.
  • Non-reversible changes

Hypertrophy and Atrophy

• Hypertrophy: Increase in tissue size due to cell enlargement.
  • Example: Left ventricular hypertrophy (LVH) in hypertension.
• Atrophy: Decrease in tissue/organ size due to reduced cell size and numbers.

Microscopic Appearance of Normal Tissue

• Architecture: Surface epithelium, glands, bundles, etc.
• Cells: Uniform size and shape, preserved polarity, uniform nuclei, regular outlines, mitosis limited to the basal layer, normal N/C ratio.
• Nucleus: at the lower pole of the cell

Hyperplasia and Metaplasia

• Hyperplasia: Increased cell number due to increased cell proliferation. Physiological or pathological; reversible.
• Metaplasia: Change of adult cell type to different adult cell type. Reversible change where one cell type is replaced by another.

Dysplasia

• Dysplasia: Disorderly growth of cells in tissues (Loss of uniformity of individual cells, architectural orientation).
• Architecture: Disorderly arrangement in epithelium, loss of maturation.
• Cells: Pleomorphic (variation in size and shape), lost polarity.
• Nuclei: Variation in size and shape, nuclear enlargement, hyperchromatic nuclei, increased N/C ratio, mitosis not confined to the basal layer.

Dysplastic Cells vs. Normal Cells

• Arrangement: Dysplastic - disordered; Normal - arranged
• Size and shape: Dysplastic - variations; Normal - uniform
• Maturation: Dysplastic - loss; Normal - preserved
• Polarity: Dysplastic - loss; Normal - preserved
• Nuclear size & shape: Dysplastic - enlargement, irregularity; Normal - uniform
• Chromatin: Dysplastic - hyperchromatic; Normal - normochromatic
• N/C ratio: Dysplastic - increased; Normal - normal
• Mitosis: Dysplastic - not confined to basal layer; Normal - confined to basal layer.

Dysplasia Progression

• Reversible: Low-grade dysplasia may regress if the persistent injury is removed.
• Progressive: High-grade dysplasia may progress to carcinoma in situ, followed by invasive carcinoma.

What is a Neoplasm?

• Neoplasia means "new growth."
• Neoplasms are characterized by purposeless and autonomous cell growth.
• Differentiate benign/malignant tumors based on their gross and microscopic examination.

Benign vs. Malignant Neoplasms (Gross Features)

• Benign Tumors: Slow growth, well-defined edges/margins, encapsulated, no invasion, do not spread to distant sites.
• Malignant Tumors: Rapid growth, irregular edges/margins, not encapsulated, invasive, spread to distant sites.

Classification and Nomenclature of Benign and Malignant Neoplasms

• Neoplasms are named on the basis of their cell/tissue of origin.
  • Epithelial, connective tissue, lymphoid/hematological, mixed tissue.
• Specific terms are used (e.g. suffix "-oma" for benign epithelial tumors).

Main Classifications: Benign and Malignant Tumors

• Benign: Epithelial, connective tissue, fat/lipid, cartilage, bone, muscle
• Malignant: Carcinoma(Epithelial). Sarcoma(Connective tissue), Lipomas, Adenocarcinoma.

Other Tumors

• Lymphoid/Hematopoietic: Lymphomas, leukemia
• Melanocytes: Melanoma (malignant), Nevus (benign)
• Embryonic Tissue: Teratomas (malignant)

Teratomas of the Ovary

• Benign tumors composed of mixed tissues (e.g., skin, hair, bone, cartilage).
• Other common sites (e.g., testis) but testicular teratomas are malignant.

Pathological Changes in Tumors

• Gross (Macroscopic): Describes physical characteristics (size, shape, color, number, location)
• Microscopic: Examines the cells and tissue structures at high magnification

How to Describe Gross Pathological Changes

• Shape of lesion (e.g., ulcer, nodule, mass, polyp)
• Number of lesions (e.g., single, multiple, 2,3 etc)
• Location of lesion
• Shape of lesion (e.g., rounded, oval ...etc)
• Size of lesion
• Color of lesion
• Surface of lesion (e.g., intact, smooth, ulcerated)
• Outline/Border (e.g., regular/irregular, well demarcated/poorly demarcated)
• Relationship to surrounding structures.

A Pathological Lesion of the Uterus

• Well-Circumscribed Masses: Multiple, rounded, white, regular well-demarcated masses, pushing the surrounding structure without invasion.

Is it Benign or Malignant?

• Benign: Leiomyoma of the uterus

Adenoma of Colon

• Lesion: Polyps
• Location: Above mucosa
• Shape: Rounded Mass with a neck
• Size: ~ 2 x 2 cm
• Color: Brown/Reddish
• Outline/ Border: regular well demarcated
• Relation to surrounding structure: above surface with no invasion

Benign Tumors

• Well differentiated: Tumors resemble their tissue of origin
• Examples of benign tumors: - Adenoma - Lipoma
  • Leiomyoma

Malignant Tumors

• Grades: 4 grades of differentiation (well-differentiated, moderately differentiated, poorly differentiated, anaplastic)

Microscopic Pathological Changes of Tumors

• (A) Parenchyma: Arrangement (tubules, glands, sheets, cords, papillae), Cell size and shape (uniform or pleomorphic), nuclei (shape, chromatin, N/C ratio), mitosis (rare, frequent, normal or abnormal).
• (B) Stroma: Connective tissue, blood vessels, and host-derived inflammatory cells.

Invasive vs. Non-Invasive Cells

• Benign: Cells remain confined to their areas
• Malignant: Cells invade surrounding tissues

Metastasis (Spread) of Malignant Tumors

• Process: Neoplastic cells from primary tumors spread to distant sites.
• Steps: Invasion into surrounding tissues; detachment within vessels; transport in emboli; extravasation (movement from vessel to tissue) and growth at new sites.
• Routes: Blood vessels, lymphatics, and transcoelomic spread. (across body cavities e.g. spread of malignant cells from gastric carcinoma too the ovaries through peritoneal cavity)

Metastatic Malignant Tumors in the Liver

• Liver containing multiple metastases, noted with central necrosis within nodules.

Grading of Adenocarcinoma of Colon

• 4 grades of differentiation: well-differentiated, moderately-differentiated, poorly-differentiated, and undifferentiated (anaplastic).

Squamous Cell Carcinoma

• Gross Appearance: Ulcer with raised everted edges, irregular outline; red necrotic floor
• Microscopic features: Keratin pearls, malignant sheet, malignant cells

Transitional Cell Carcinoma of the Kidney

• Gross: friable, necrotic tumor mass, in renal pelvis
• Microscopically: transitional cell carcinoma

Adenocarcinoma of the Colon

• Lesion appearance: ulcerative mass with irregular outline
• Edge: raised everted edges
• Floor: red necrotic floor

Endometrial Carcinoma, Uterus

• Type: Grade 1 adenocarcinoma
• Characteristics are described in the slides

Breast Carcinoma

• Describe gross and microscopic features