MMB (035) Bone and Soft tissue tumours I Flashcards
(120 cards)
What is metaplasia ?
an adaptive, reversible change in which one adult “mature, differentiated” cell type is replaced by another of the same category (epithelial or mesenchymal).
What is dysplasia ?
A non-neoplastic, disordered epithelial cell proliferation ;
• Low-grade changes may be reversible
• High-grade dysplasia is premalignant
Cause of Dysplasia ?
Chronic irritation ;
Examples:
-Chronic cervicitis → cervical dysplasia
-Bilharzial Cystitis → urothelial dysplasia
Microscopic features of Dysplasia ?
Atypia + loss of normal orientation “polarity”
Features of atypia ?
- Pleomorphism
- Hyperchromatism
- Increased N/C
- Increased mitosis
Comment on this epidermal slide
Abnormal epidermis with irregular scattering of keratinocytes showingloss of polarity
Grades of Dysplasia ?
Atypia& loss of polarity ;
-Mild: epidermal lower 1/3
-Moderate: 2/3 of epidermis
-Severe: whole epidermal thickness
Neoplasia ?
-an acquired abnormality in which there is abnormal, uncoordinated and excessive cell growth
-persists after the initiating stimulus has been removed (autonomous)
-involves genetic alterations in the neoplastic cells
Detailed definition of Neoplasm ?
A neoplasm is a persistent, abnormal mass of tissue, the growth of which exceeds & is uncoordinated with that of the normal tissue and persists in the same manner after cessation of the stimulus that evoked it.
: The suffix …..oma = neoplasm
Main 2 components of neoplasms ?
- Transformed, neoplastic cells
- Supporting stroma: connective tissue & blood vessels.
Tumor vascularization is affected by (cells) :
- Tumor cells
- Inflammatory cells
Both
» (secrete) tumor- associated angiogenic factors
Compare between malignant and benign tumors accoriding to :
-invasion
-localization
- growth rate
- resemblance to parent tissue
Mode of growth for solid tissue benign tumors ?
Mode of growth for solid tissue surface tumors ?
Non-encapsulated benign tumors include:
-leiomyomas
- hemangiomas
-lymphangiomas
-nevi
-benign surface epithelial tumors
Cell morphology of Benign tumors ?
a. Tumor cells mimic cells of original tissue.
b. Cells are small, uniform in size and shape.
c. N/C is preserved.
d. Mitotic figures are minimal and normal.
Benign Tumor architecture ?
a. Same histological pattern as tissue of origin
b. Well- developed vascular stroma
A major Effect of benign tumors on neighbouring tissue ?
compress neighboring tissue»_space; atrophy
Comment on the possibility of benign tumors recurrence
No recurrence if totally excised
Ways by which a mass neoplasm can be described ?
-Hard
-Fixed
-Irregular
-Ill-defined
Ways by which a surface neoplasm can be described ?
- Polypoid
- Ulcerative mass
- Infiltrative
Anaplasia ?
lack of differentiation