Chapter 1 - Anatomy of the GU Tract and Histology of GU Tumours
Prostate cancer is very common. A complete examination of the prostate will reveal cancer in 50% of men at the age of 50 and >75% at the age of 75 years.
Accordingly, precursor lesions are even more common in the prostate and many patients have more than one spatially separated prostate cancer.
Normal prostate epithelium is characterised by the presence of two cell layers: basal cells and acinar cells.
Prostate biopsy is the only tool for establishing a definitive diagnosis of prostate cancer.
Findings in prostate biopsies include: normal, prostatic intraepithelial neoplasia (PIN), atypical small acinar proliferation (ASAP), and carcinoma.
PIN is the precursor lesion of prostate cancer. ASAP is a diagnostic category that includes all changes that are suspicious for cancer but not unequivocally diagnostic.
Prostate cancer is entirely composed of atypical cells, while basal cells are completely lost. Gleason grade is the strongest predictor of tumour aggressiveness.
In contrast to all other grading systems, the Gleason grade is purely based on tumour architecture and does not consider any cytological changes.
It distinguishes 5 sets of histological patterns with increasing “dedifferentiation” from 1 to 5.
- What is the precursor lesion of prostate cancer?
- What is the meaning of “ASAP” and when is this term used?
- What is the characteristic of Gleason grading?