A pathologist examines two separate biopsies from a 62-year-old woman. Biopsy A from the stomach shows replacement of gastric glands with intestinal-type glands (intestinal metaplasia). Biopsy B from the cervix shows crowded cells with increased nuclear size, irregular nuclear membranes, and abnormal mitotic figures, but the epithelium remains intact without invasion. Which finding best discriminates metaplasia (Biopsy A) from dysplasia (Biopsy B)?

Explanation

## Metaplasia vs. Dysplasia: Cellular Maturation as the Key Discriminator ### Pathological Definitions **Metaplasia** = Reversible replacement of one mature, differentiated cell type with another mature, differentiated cell type in response to chronic injury. **Dysplasia** = Irreversible pre-malignant lesion characterized by loss of cellular differentiation, disorderly growth, and increased mitotic activity. ### Comparison Table | Feature | Metaplasia | Dysplasia | |---------|-----------|----------| | **Cellular differentiation** | Maintained; cells are mature | Lost; cells are immature | | **Maturation gradient** | Present (basal → surface) | Absent or reversed | | **Mitotic figures** | Normal, in basal layer only | Abnormal, throughout epithelium | | **Nuclear size** | Normal | Enlarged (high N:C ratio) | | **Basement membrane** | Intact | Intact (by definition; invasion = carcinoma) | | **Reversibility** | Yes, if stimulus removed | No; pre-malignant | | **Malignant potential** | Low unless dysplasia supervenes | High; ~30–50% progress to cancer | ### Key Point: **Maintained cellular differentiation and maturation is the hallmark that separates metaplasia from dysplasia.** In metaplasia, cells are fully mature and organized from basal to luminal surface. In dysplasia, this maturation is lost — immature cells populate the entire thickness of the epithelium. ### Clinical Pearl: Intestinal metaplasia of the stomach (Biopsy A) is a response to chronic Helicobacter pylori infection or bile reflux. The glandular cells are well-differentiated and organized. Cervical dysplasia (Biopsy B), often HPV-driven, shows crowded immature cells throughout the epithelium with loss of the normal basal-to-luminal maturation sequence. ### High-Yield: **Dysplasia = loss of maturation; Metaplasia = change of cell type but retention of maturation.** ### Mnemonic: **DISLOSS** — DISplasia = LOSS of maturation. **METAMATURE** — METAplasia = MATURe replacement.