Learning Objectives
Analyze the histological vocabulary of dermatology to interpret skin biopsies. Differentiate between cellular-level changes such as Acantholysis (separation) and Acanthosis (thickening), and recognize the specific diagnostic patterns of Spongiosis and Parakeratosis.
1. Structural and Thickness Changes
| Term |
Microscopic Characteristics |
Classic Examples |
| Hyperkeratosis |
Increased thickness of the stratum corneum. |
Psoriasis, calluses. |
| Acanthosis |
Epidermal hyperplasia (increased stratum spinosum). |
Acanthosis nigricans, Psoriasis. |
| Hypergranulosis |
Increased thickness of the stratum granulosum. |
Lichen planus. |
2. Abnormal Keratinization and Nuclei Retention
| Term |
Microscopic Characteristics |
Classic Examples |
| Parakeratosis |
Retention of nuclei in the stratum corneum (rapid turnover). |
Psoriasis, actinic keratosis. |
| Dyskeratosis |
Abnormal, premature keratinization of individual cells. |
Squamous cell carcinoma. |
3. Intercellular Fluid and Separation
| Term |
Microscopic Characteristics |
Classic Examples |
| Spongiosis |
Accumulation of edematous fluid in intercellular spaces. |
Eczematous dermatitis. |
| Acantholysis |
Separation of epidermal cells (loss of desmosomes). |
Pemphigus vulgaris. |
Activity:
High-Yield Mnemonics:
- Spongiosis: Think of a Sponge soaking up edema fluid.
- Acantholysis: Lysis means breakdown of cell-to-cell connections.
- Parakeratosis: Persistent nuclei in the stratum corneum.
Activity:
