1. Section 2 Atypia

2. Definition: this refers to the extent to which tumor cells different from their origin normal cells.
obviously: poor differentiation, malignant
slightly: well differentiation, benign

3. 1. Atypia of tumor tissue structure
benign tumor: slightly change in pattern, including structure
malignant tumor: obviously, disorder
arrangement, direction, cell layers, and cell rank order.

4. 2. Atypia of tumor cells Benign tumor: slightly
Malignant tumor: obviously
(1) Pleomorphism: of tumor cells
Variation in size and shape
Some extremely small and primitive appearing
Some many times larger than their neighbors, even tumor giant cells

5. (2) Pleomorphism of nuclei
① Large nuclear the nuclear to cytoplasmic
ratio may approach 1:1 (the normal 1:4~6)
② Hyperchromatic dark staining (containing
abundance of DNA)
③ Sometimes have two nuclei, even multi
nuclei giant cell.
④ The nuclear shape is usually variable.

6. ⑤ Numerous mitoses
the most important is appear atypical, bizarre mitotic figures as non- symmetry, tripolar, quadripolar, multipolar spindles and abortion types pathologic mitoses.
⑥ Nuclear membrane became thick
the chromatin is often coarsely clumped
⑦ Large nucleoli

7. (3) Changes in cytoplasm
Basophilic

8. Atypia (Quoted from Rubbin’s《Basic Pathology》)

9. non- symmetry, tripolar, quadripolar, multipolar spindles and abortion types pathologic mitoses.

10. non- symmetry(left), tripolar(middle), and abortion types(right) of pathologic mitoses.

11. 3. Atypia of tumor ultrastructure
The difference mainly in quantity compared with normal cells
(1) Large nuclei and nucleoli, irregular shape, and multiply.
(2) Heterochromatin increase, coarsely clumped and distributed along the nuclear membrane.
(3) Mitochondrion, endoplasmic reticulum, and
Golgi complex hypogenesis, abnormal shape and decreased number.

12. (4) More dissociative nuclein
(5) More lysosomes
(6) The cellular junction decrease
(7) Microvillus: variation in shape, number, and arrange mount