Pathology of Prostate Cancer



Fig. 3.1
Normal prostate transition zone



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Fig. 3.2
Normal prostate peripheral zone


The histological structure of the acini and ducts is identical. The cells that form the gland are arranged in two layers, basal and luminal or secretory cells.



3.3 Morphology of Prostate Cancer


Prostate cancer is a glandular malignant neoplasia (adenocarcinoma), mostly of secretory or luminal phenotype with only a minimal percentage of cases having another histological morphology. The typical morphological features are microglandular monolayer proliferation with absence of basal cells and irregular nuclei with large nucleoli, which are multiple in some cases.

Using McNeal’s model, around 70% of prostate carcinomas are in the peripheral zone (90% in the posterior or posterolateral area and 10% in the anterior horns) [5, 6], 7% are exclusively in the transition zone, and the remainder are in both zones or of indeterminate location [7]. Tumors with a smaller volume tend to be located in the apical portion, but as their volume increases, the subvesical portion also becomes involved [8]. Multifocality is present in approximately 80% of patients, half of whom have more than two nodules with frequent heterogeneous features [9].


3.4 Morphological Variability of Acinar Prostate Cancer


The aggressiveness of cancer is related to the increase in genetic (chromosomal) changes. The nuclear changes produce cytoplasmic and intercellular adhesion molecule lesions expressed by changes in the architectural arrangement of the neoplastic cells.

For prostate cancer grading, WHO recommends the Gleason score with the 2014 International Society of Urological Pathology (ISUP) criteria and grade groups. The Gleason system only evaluates the architectural changes [10]. The ISUP guidelines claimed to be more precise in the criteria for every pattern.

Patterns 1, 2, and 3 consist in discrete glandular proliferation with marked variation in size and shape, with infiltration among nonneoplastic prostate acini and with different quantities of interglandular stroma (Fig. 3.3).Pattern 4 has four different subtypes:



  • Fused glands composed of a group of glands that are no longer completely separated by stroma (Fig. 3.4).


  • Cribriform glands representing a glandular proliferation with multiple punched-out lumina (Fig. 3.5).


  • Poorly defined glands with ill-formed or absent glandular lumina (Fig. 3.6). Classification for this subtype requires the presence of a cluster of such glands, to exclude the possibility of tangentially sectioned glands for Gleason pattern 3.


  • Glomeruloid glands. These are dilated glands containing a cribriform proliferation attached to only one edge of the gland, resulting in the structure resembling a glomerulus (Fig. 3.7).


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Fig. 3.3
Prostate adenocarcinoma pattern Gleason 3. Notice the tumoral growth among normal prostate glands


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Fig. 3.4
Prostate adenocarcinoma, Gleason pattern 4, fused type


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Fig. 3.5
Prostate adenocarcinoma, Gleason pattern 4, cribriform type


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Fig. 3.6
Prostate adenocarcinoma, Gleason pattern 4, poorly or ill-defined gland type


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Fig. 3.7
Prostate adenocarcinoma, Gleason pattern 4, glomeruloid type

Pattern 5 is essentially no glandular differentiation with or without necrosis (Fig. 3.8).

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Fig. 3.8
Prostate adenocarcinoma, Gleason pattern 5

The grade groups proposed by ISUP correspond to various combinations of these different patterns (Table 3.1). These grade groups show a good correlation with prognosis in prostate carcinoma in biopsy and radical prostatectomy [11] and with the number of genetic changes [12].


Table 3.1
Different combinations of Gleason patterns in the different grade groups proposed by ISUP



















Group

Gleason

Description

1

≤6

Only individual discrete well-formed glands

2

3 + 4 = 7

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May 5, 2018 | Posted by in MAGNETIC RESONANCE IMAGING | Comments Off on Pathology of Prostate Cancer
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