Gleason Grading of Prostatic Ca

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Gleason Grading of Prostatic Ca
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Introduction

• Gleason grade, serum PSA the rectal examination
  of the prostate together provide the best
  estimates of tumor stage and aggressiveness.
• DF Gleason in 1974 and 1977 published a prostate
  cancer grading system that is now universally
  embraced. His system grades the cancer by looking
  primarily at the patterns of cancerous glands.

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Gleasons Grade

• picture adapted from Gleason's 1977 article
  demonstrating the changes in gland pattern as one
  goes from grade 1 to grade 5 cancer. The glands
  in grade 1 cancer are small and round. Grade 5
  cancer is hardly forming glands at all.

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• The Gleason pattern system correlates very well
  with behavior at the extremes Gleason 11 tumors
  grow slowly and rarely spread. Gleason 45 tumors
  are often widely metastatic at the time of
  diagnosis. In the commoner intermediate grade
  tumors, however, behavior is extremely variable.

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Normal Prostate gland
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High grade PIN (Dysplasia)
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Gleason Grade 11
Picture Shows nodule of Gleason 1 prostate
cancer, showing a pattern of small uniform glands
organized into a nodular pattern. Around is
hyperplastic benign glands.
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Gleason Grade 11
High power view showing a pattern of small
uniform glands organized into a nodular pattern.
Upper left and lower right corner are
hyperplastic benign glands.
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Gleason Grade 22

• The cancer focus is not circumscribed (unlike in
  Gleason grade 1). The malignant glands show
  slight variation in size and shape however, the
  glandular contours are slightly irregular. Large
  nuclei with prominent nucleoli (blue dots inside
  nuclei).

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Gleason Grade 11
Cancerous gland demonstrates a single layer of
cells with abnormal nuclei, containing nucleoli .
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Gleason Grade 33
Note no nodule formation, instead infiltration
shown by few benign glands in between. Note
irregular gland shape.
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Gleason Grade 33
High power back to back glands, no stroma in
between some glands.
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Gleason Grade 3

• common pattern. variation in size, shape, and
  spacing of the glands. The glands are haphazardly
  infiltrating the stroma however, they are still
  discrete (i.e. there is no fusion of glands - a
  hallmark of Gleason grade 4). Some of the glands
  have occluded or abortive lumens.

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Gleason Grade 4

• The most distinguishing feature of this grade is
  fusion of glands. The fused glands form an
  anastomosing network or cord-like arrangements
  with punched-out glandular lumens.

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Gleason Grade 5

• solid sheets without forming any discernible
  glands. Areas of necrosis may be present. The
  punched-out circular lumens seen in this case
  correspond to "signet ring-cell pattern" - a
  variant of Gleason grade 5. Other rare patterns
  such as small cell carcinoma are also included in
  grade 5 and tend to behave aggressively. Note a
  single large benign gland in the upper left
  corner.

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• Grade 1 The least common. Consists of a
  circumscribed mass of evenly placed uniform
  glands that closely resemble normal prostate
  glands
• Grade 2 Similar to Grade 1 but do not form a
  circumscribed mass. There may be slight variation
  in size, shape, and spacing of the glands. The
  glands can be seen infiltrating (spreading)
  through the surrounding stroma.
• Grade 3 The most common pattern showing
  considerable variation in size, shape, and
  spacing of the glands. Irregular infiltration of
  the surrounding stroma may impart a ragged
  appearance to the cancer focus when seen at
  low-magnification under the microscope.
• Grade 4 The most important feature of this grade
  is fusion of glands forming an anastomosing
  network punctuated by glandular lumens. Glands
  are no longer recognized as individual units.
• Grade 5 The cancer cells form solid sheets and
  clusters or may infiltrate the prostate as
  individual cells. Necrosis may be present. There
  is no attempt at gland formation by cancer.

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• Primary grade (the most common pattern)
  secondary grade (the next most common pattern
  lt5) to each tumor. Gleason score is obtained by
  adding the two values.
• If the biopsies show a tiny focus of cancer with
  features of Gleason grade 4 and no secondary
  pattern, the Gleason score would be 448 (the
  primary grade is simply doubled).
• The lowest possible Gleason score is 112 when
  there is only one pattern of Grade 1.
• The highest possible Gleason score is 5510 when
  there is only pattern grade 5.
• The most commonly observed Gleason score is
  336.

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• Gleason grading should be applied to all positive
  biopsies irrespective of the amount of cancer or
  size of biopsy.(even small focus in needle
  biopsy)
• Is cancer with Gleason score of 347 different
  from 437? - yes.
• When tertiary (third most common) and quaternary
  (fourth most common) patterns are observed in
  needle biopsies, they are usually ignored unless
  they are of higher grade. If three histologic
  grades are present and 2nd and 3rd grade are
  roughly equal in proportions, the higher grade is
  chosen to assign Gleason score. For e.g. if
  biopsies show 60 Grade 3, 20 Grade 2, and 20
  Grade 4, the Gleason score would be 347.

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• Gleason pattern 2 should satisfy the three "R's"
  Round, Regularly spaced and Relatively uniform in
  size Gleason pattern 2 cancer consists of
  predominantly round acini without sharp
  angulation or distorted shape.
• Nearly as important as acinar roundness is
  spacing - pattern 2 acini have relatively uniform
  spacing throughout the focus, unlike pattern 3,
  with variable spacing.

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Gleason Grade 5

• Even small foci of high grade cancer such as this
  showing few signet ring cancer cells in a needle
  biopsy suggest high grade cancer with poor
  prognosis. Hence not the size but the grade
  determines outcome.

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Gleason Grade 3

• Despite relative uniformity of acinar size,
  significant acinar angulation or distortion
  indicates Gleason pattern 3 rather than pattern
  2 Significant acinar angulation violates Clue
  no. 4 above, precluding pattern 2. Some areas of
  Gleason pattern 3 may have relatively uniform
  acinar size with or without crowding. This
  pattern often has acini that are smaller than
  pattern 2. The lack of acinar roundness in such
  cases separates pattern 3 from pattern 2.

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Gleason Grade 3

• If a line can be drawn around individual acini,
  no mattern how tightly packed, then the acini are
  not fused and it is pattern 3.

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Gleason Grade 4
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Grade 4

• Acinar fusion separates most cases of Gleason
  pattern 4 and 3. This is a critical cut-point in
  grading prostate cancer, as pattern 4 indicates
  poorly differentiated cancer.