Hyperplasia, Hypertrophy, Atrophy😊

Cellular Adaptations

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Hypertrophy vs. Hyperplasia

Feature
Hypertrophy
Hyperplasia
Definition
Increase in cell size
Increase in cell number
Mechanism
Increase in transcription factors:

• NFAT
• GATA
• MEF 2

Trophy → Fat (NFAT)
→ No passing through Gate (GATE)
So Me Fit → (MEF 2)
Increase in cell number by mitosis.
  • Common Examples
    • Pregnant (Gravid) Uterus
      • Hypertrophy >> hyperplasia.
      • uTerus → Trophy
    • Breast Development (Pregnancy)
      • Hyperplasia >> hypertrophy
      • P → P → P
  • Individual Examples
      • Hypertrophy
      Hypertrophy
      • Bodybuilders
      • Urinary bladder hypertrophy (stone)
      • LVH
      • Breast during Puberty
      • Endometrial hyperplasia (due to estrogen)
      • Endometrial carcinoma type 1.

      BPH → Nodular hyperplasia of the prostate
      ↳ Cause: Dihydrotestosterone (DHT).
      ↳ Testosterone → DHT
      ↳ by       5-alpha reductase type 2.
      ↳ Treatment:       Finasteride (inhibitor).
Feature
Type I Endometrial Ca
Type II Endometrial Ca
Mutation
KRAS / PTEN
P53
Histology
Endometrioid adenocarcinoma
Papillary serous or Clear cell adenocarcinoma
Grade
Low grade (1, 2)
High grade (3)
Precursor
Endometrial hyperplasia
Endometrial atrophy
Estrogen relation
A/w excess estrogen exposure
-
Frequency
Most common type
Less common
Prognosis
Good prognosis
Poor prognosis

Atrophy

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  • Definition: Decrease in size and number of cells.
  • Mechanism: Ubiquitin proteasome pathway.
  • Mnemonic: Atrophy → when U Quitting (Ubequitin)

Examples:

Type of Atrophy
Cause / Example
Disuse atrophy
Organ not used.
Example: Muscle atrophy after fracture (cast).
Malnutrition
Lack of food.
Ischemic atrophy
Lack of blood supply.
Denervation atrophy
Lack of nerve supply.
Endometrial atrophy
Old age, post-menopausal females.

Atrophy and Cancer:

Pathology
Examples
Prognosis
Endometrial atrophy
Endometrial cancer type 2
Worse prognosis
Endometrial hyperplasia
Endometrial cancer type 1
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Lymph Node Hyperplasia

  • Follicular hyperplasia
  • Paracortical hyperplasia
  • Sinus histiocytosis (reticular hyperplasia)

Paracortical Hyperplasia

  • Acute Viral Infections produce paracortical Hyperplasia
  • Seen in T-cell–containing paracortical region of lymph node
    • Caused by T-cell–mediated immune responses

Features

  • Immunoblasts
  • Activated T-cells (3–4 times size of resting lymphocytes)
    • Round nuclei
    • Open chromatin
    • Several prominent nucleoli
    • Moderate pale cytoplasm
  • Hypertrophy of sinusoidal and vascular endothelial cells
  • Infiltration with macrophages and eosinophils