Prostatic adenocarcinoma: Gleason and grade groups
- Lesion
Small crowded glands without basal cells infiltrate the peripheral prostate; the Gleason system turns their pattern into a grade group.
What it is
Most prostate cancers arise in the peripheral zone, near the rectum, and are multifocal. Under the microscope the malignant glands are small, crowded and infiltrative, lined by a single layer of cells with prominent nucleoli and no basal cells; perineural invasion is common. Grading uses the Gleason patterns (3 to 5 in practice), summed for the two commonest patterns and converted into five grade groups that predict outcome. Staging uses TNM: organ-confined, extraprostatic extension, seminal vesicle invasion, invasion of adjacent organs. Spread goes to pelvic nodes and to bone, producing osteoblastic metastases. Rare tumours of the prostate include ductal and neuroendocrine carcinomas, urothelial carcinoma and sarcomas.
Structure
- Gross: firm, gritty, grey-yellow areas that are hard to see; best found by targeted biopsy.
- Microscopy: small glands back to back with a single cell layer, enlarged nuclei and nucleoli, no basal layer.
- Immunohistochemistry confirms the absence of basal cells and shows prostatic origin (NKX3.1, PSA) in metastases.
Clinical notes
- PSA rises with cancer but also with BPH, prostatitis and instrumentation; free PSA and PSA density refine its meaning.
- Back pain in an older man with high PSA and sclerotic vertebral lesions suggests metastatic prostate cancer, with risk of cord compression.
In the lab
- PSA is used for detection and for follow-up after treatment, where a rising level signals recurrence.
Test yourself
Think of the answer, then tap the question to see it.
What immunostains show the absence of basal cells in prostate cancer?
p63 and high-molecular-weight cytokeratin are negative, while AMACR is positive in the tumour cells.
Which grade group corresponds to a Gleason score of 3+4?
Grade group 2.
What type of bone metastasis is typical of prostate cancer?
Osteoblastic (sclerotic) metastases, mostly in the axial skeleton.
Elsewhere in DurgiPedia
- Prostate-specific antigen (PSA)
- Grading and staging: what TNM means
- Pathways of spread and the usual metastatic sites
- Immunohistochemistry: the principle and the markers to know
- Epididymis, vas deferens, seminal glands and prostate
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Prostate Cancer (StatPearls (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.