Difference between revisions of "Evaluation of suspected malignancies"

From patholines.org
Jump to navigation Jump to search
(29 intermediate revisions by the same user not shown)
Line 3: Line 3:
 
|author2=
 
|author2=
 
}}
 
}}
{{General notes}}
+
For [[evaluation]] of '''suspected malignancies''' such as '''tumors''', the most important aspect is whether it is benign or malignant. If malignant, then staging is necessary.<ref name=cancer>{{cite web |url= http://www.cancer.gov/cancertopics/factsheet/detection/staging |title=Cancer staging |date= |publisher=National Cancer Institute |accessdate=4 January 2013}}</ref> There are generally specific criteria for various forms of tumors, which should be used whenever applicable, but following are some generalizations.
The most important aspects of a tumor is whether it is malignant or not, and staging.
+
 
 +
A general approach is to start looking at the slide which seems to contain most tumor (excluding any necrosis), facilitating a diagnosis, and shows what kind of cells to look for in the periphery.
 +
 
 +
==Benign or malignant==
 +
[[File:Normal and cancer cells structure.jpg|thumb|Cellular features of malignant cells versus normal cells.]]
 +
{|class="wikitable"
 +
!  !! Benign<ref name=amboss>{{cite web|url=https://www.amboss.com/us/knowledge/General_oncology|title=General oncology|website=Amboss|accessdate=2020-01-29}}</ref> !! Malignant<ref name=amboss/>
 +
|-
 +
! Gross examination
 +
|
 +
*Well demarcated from surrounding tissue
 +
|
 +
*Usually no tumor capsule
 +
Possibly:
 +
*Necrosis
 +
*Infiltration or invasion into surrounding tissue
 +
*Bleeding
 +
|-
 +
! Microscopy
 +
| Almost no irregularities of cellular structures
 +
| Nuclear atypia:
 +
*Enlargement
 +
*Pleomorphism
 +
*Nuclear polychromasia, which means variability in nuclear chromatin content.
 +
*Numerous mitotic figures
 +
|}
 +
 
 +
===Overall diagnosis===
 +
For specific diagnoses by organ system, see anatomic diagram on Patholines '''[[Main page]]'''. This resource will give the main steps towards reaching a diagnosis, but before making a tumor diagnosis, always confirm with [https://publications.iarc.fr/Book-And-Report-Series/Who-Classification-Of-Tumours The WHO Classification of tumors], and generally an experienced pathologist as well until you feel confident.
 +
 
 +
Two relatively common forms of tumors are:
 +
<gallery mode=packed>
 +
File:Non-proliferative versus proliferative colonic crypts.jpg|'''Gland-like tumors''' (image shows normal colonic crypt compared to an adenoma)
 +
File:Histopathology of leiomyoma of the ileocecal valve.jpg|'''Spindle-cell tumors''' (image shows a leiomyoma)
 +
</gallery>
 +
 
 +
'''Gland-like tumors''' are mainly evaluated for cellular atypia, architectural dysplasia and invasion, and thereby classified into the following main categories:
 +
*'''Hyperplastic''' lesions, lacking significant atypia
 +
*'''Adenomas''', which can range from mild to high-grade dysplastic, yet are not invasive
 +
*'''Adenocarcinomas''', with the main criterion being invasiveness. Evaluate specifically by location when possible. Some specific locations included in this resource:
 +
:*[[Colorectal adenocarcinoma]]
 +
:*[[Prostate adenocarcinoma]]
 +
:*[[Lung adenocarcinoma]]
 +
:*[[Bladder adenocarcinoma]]
 +
:*[[Esophageal adenocarcinoma]]
 +
:*[[Endometrial adenocarcinoma]]
 +
 
 +
For '''Spindle-cell tumors''', the shape of the nuclei is a clue to the diagnosis, with the following tendency:
 +
*Pointed on both ends: True fibroblastic tumors
 +
*Pointed on one end and blunted on the other ("bullet-shaped"): Neural
 +
*Blunted on both ends ("cigar-shaped"): Smooth muscle
 +
*Triangular: Myofibroblastic
 +
Evaluate specifically by location when possible, such as [[spindle-cell tumors of the midgut]].
 +
 
 +
Further pinpointing of a specific tumor type is often attained by thinking of one or more possible diagnoses, and looking up their '''differential diagnoses''', followed by comparing their microscopic descriptions and multiple micrographs with the case at hand. When two or more diagnoses seem to fit with the case at hand, consider performing '''immunohistochemistry'''. Find relevant target proteins that are expected to stain substantially differently between the possible diagnoses. If it's not evident from initial sources, you may use Immunoquery.com which will generally suggest the most relevant target proteins to distinguish the suspected conditions at hand.
  
 
==Staging==
 
==Staging==
The primary focus of tumor evaluation is to distinguish benign from malignant types, and in case of malignancy the primary focus is to determine its stage, generally by the TNM classification:<ref>{{cite web |url= http://www.cancer.gov/cancertopics/factsheet/detection/staging |title=Cancer staging |date= |publisher=National Cancer Institute |accessdate=4 January 2013}}</ref>
+
Staging is generally done by TNM classification. Specific TNM systems should be used whenever applicable, mainly the manual by the American Joint Committee on Cancer (AJCC) if you can access it. {{further|Secrets}}<noinclude>.</noinclude> Otherwise, a general system may be used:<ref name=cancer/>
 
{|class="wikitable"
 
{|class="wikitable"
 
|
 
|
Line 26: Line 80:
 
|}
 
|}
  
===Typing and grading===
+
Put your main '''focus''' on features that will determine the final stage. For example, if you see a lymph node involved by cancer, the presence or absence of lymphatic invasion is no longer critical, but rather the presence or absence of additional involved nodes or distant metastasis.
Beyond determining overall malignancy, probable origin and staging, classification of tumors into a specific histopathologic type or grade is of relatively less value. In cases of clearly non-malignant tumors where it is difficult to determine the specific histopathologic type or grade, it is generally acceptable to conclude the evaluation and report it as such, unless the clinician specifically requests otherwise. For potentially malignant or high-risk tumors, typing and grading often still affects the management.
+
 
 +
==Radicality==
 +
[[File:Histopathology of radically excised basal-cell carcinoma with separation artifact.jpg|thumb|250px|If tumor is seen at edge of the sample, but it is not inked, consider confirming the finding with adjacent microtomy levels, especially if no ink is seen on an inked surgical margin. In this case, a separation artifact in top image has removed a surgical margin of connective tissue, seen on adjacent microtomy section in bottom image.]]
 +
Determine if malignant cells are located close to, or even in, any surgical resection margins.
 +
 
 +
==Lymphovascular invasion==
 +
Lymphovascular invasion should always be mentioned. When present at margins, it does ''not'' count as tumor extension.
 +
<gallery mode=packed>
 +
File:Histopathology of endometrial cancer with lymphovascular invasion.jpg|Endometrial cancer with lymphovascular invasion.
 +
File:Histopathology of typical micropapillary urothelial carcinoma infiltrating the lamina propria - crop.jpg|If unsure whether a case is true lymphovascular invasion or a retraction artifact (imaged), use immunohistochemistry for D2-40 to highlight lymphatic vessels or CD-31 for blood vessels.
 +
</gallery>
 +
 
 +
==Typing and grading==
 +
[[File:Histopathology of pancreatic adenocarcinoma with treatment effect.jpg|thumb|Also note "treatment effect", seen as fibroelastotic tissue, here with scattered remaining tumor cells.]]
 +
Beyond determining overall malignancy diagnosis (such as adenocarcinoma), probable origin and staging, classification of tumors into a specific histopathologic type or grade is generally of relatively less value. In cases of clearly non-malignant tumors where it is difficult to determine the specific histopathologic type or grade, it is generally acceptable to conclude the evaluation and report it as such, unless the clinician specifically requests otherwise. For potentially malignant or high-risk tumors, typing and grading often still affects the management.
 +
 
 +
==Additional slices==
 +
Additional slices are indicated in the following situations:
 +
*Re-excision does not identify tumor cells in a clearly non-radical primary excision or biopsy.<ref group="notes">In such cases, step slices are taken rather than serial ones.</ref>
 +
*The most aggressive pattern is seen in the last available section, in which case more sections are indicated (from the same paraffin block if additional tissue is not available).
 +
 
 +
==Reporting==
 +
{{CAP}}
 +
{{Reporting}}
 +
<noinclude>
 +
{{General notes}}
 
{{Bottom}}
 
{{Bottom}}
 +
</noinclude>

Revision as of 12:05, 11 January 2022

Author: Mikael Häggström [note 1]
For evaluation of suspected malignancies such as tumors, the most important aspect is whether it is benign or malignant. If malignant, then staging is necessary.[1] There are generally specific criteria for various forms of tumors, which should be used whenever applicable, but following are some generalizations.

A general approach is to start looking at the slide which seems to contain most tumor (excluding any necrosis), facilitating a diagnosis, and shows what kind of cells to look for in the periphery.

Benign or malignant

Cellular features of malignant cells versus normal cells.
Benign[2] Malignant[2]
Gross examination
  • Well demarcated from surrounding tissue
  • Usually no tumor capsule

Possibly:

  • Necrosis
  • Infiltration or invasion into surrounding tissue
  • Bleeding
Microscopy Almost no irregularities of cellular structures Nuclear atypia:
  • Enlargement
  • Pleomorphism
  • Nuclear polychromasia, which means variability in nuclear chromatin content.
  • Numerous mitotic figures

Overall diagnosis

For specific diagnoses by organ system, see anatomic diagram on Patholines Main page. This resource will give the main steps towards reaching a diagnosis, but before making a tumor diagnosis, always confirm with The WHO Classification of tumors, and generally an experienced pathologist as well until you feel confident.

Two relatively common forms of tumors are:

Gland-like tumors are mainly evaluated for cellular atypia, architectural dysplasia and invasion, and thereby classified into the following main categories:

  • Hyperplastic lesions, lacking significant atypia
  • Adenomas, which can range from mild to high-grade dysplastic, yet are not invasive
  • Adenocarcinomas, with the main criterion being invasiveness. Evaluate specifically by location when possible. Some specific locations included in this resource:

For Spindle-cell tumors, the shape of the nuclei is a clue to the diagnosis, with the following tendency:

  • Pointed on both ends: True fibroblastic tumors
  • Pointed on one end and blunted on the other ("bullet-shaped"): Neural
  • Blunted on both ends ("cigar-shaped"): Smooth muscle
  • Triangular: Myofibroblastic

Evaluate specifically by location when possible, such as spindle-cell tumors of the midgut.

Further pinpointing of a specific tumor type is often attained by thinking of one or more possible diagnoses, and looking up their differential diagnoses, followed by comparing their microscopic descriptions and multiple micrographs with the case at hand. When two or more diagnoses seem to fit with the case at hand, consider performing immunohistochemistry. Find relevant target proteins that are expected to stain substantially differently between the possible diagnoses. If it's not evident from initial sources, you may use Immunoquery.com which will generally suggest the most relevant target proteins to distinguish the suspected conditions at hand.

Staging

Staging is generally done by TNM classification. Specific TNM systems should be used whenever applicable, mainly the manual by the American Joint Committee on Cancer (AJCC) if you can access it. Further information: Secrets . Otherwise, a general system may be used:[1]

T: size or direct extent of the primary tumor

    • Tx: tumor cannot be assessed
    • Tis: carcinoma in situ
    • T0: no evidence of tumor
    • T1, T2, T3, T4: size and/or extension of the primary tumor

N: degree of spread to regional lymph nodes

    • Nx: lymph nodes cannot be assessed
    • N0: no regional lymph node metastasis
    • N1: regional lymph node metastasis present; at some sites, tumor spread to closest or small number of regional lymph nodes
    • N2: tumor spread to an extent between N1 and N3 (N2 is not used at all sites)
    • N3: tumor spread to more distant or numerous regional lymph nodes (N3 is not used at all sites)

M: presence of distant metastasis

    • M0: no distant metastasis
    • M1: metastasis to distant organs (beyond regional lymph nodes)

Put your main focus on features that will determine the final stage. For example, if you see a lymph node involved by cancer, the presence or absence of lymphatic invasion is no longer critical, but rather the presence or absence of additional involved nodes or distant metastasis.

Radicality

If tumor is seen at edge of the sample, but it is not inked, consider confirming the finding with adjacent microtomy levels, especially if no ink is seen on an inked surgical margin. In this case, a separation artifact in top image has removed a surgical margin of connective tissue, seen on adjacent microtomy section in bottom image.

Determine if malignant cells are located close to, or even in, any surgical resection margins.

Lymphovascular invasion

Lymphovascular invasion should always be mentioned. When present at margins, it does not count as tumor extension.

Typing and grading

Also note "treatment effect", seen as fibroelastotic tissue, here with scattered remaining tumor cells.

Beyond determining overall malignancy diagnosis (such as adenocarcinoma), probable origin and staging, classification of tumors into a specific histopathologic type or grade is generally of relatively less value. In cases of clearly non-malignant tumors where it is difficult to determine the specific histopathologic type or grade, it is generally acceptable to conclude the evaluation and report it as such, unless the clinician specifically requests otherwise. For potentially malignant or high-risk tumors, typing and grading often still affects the management.

Additional slices

Additional slices are indicated in the following situations:

  • Re-excision does not identify tumor cells in a clearly non-radical primary excision or biopsy.[notes 1]
  • The most aggressive pattern is seen in the last available section, in which case more sections are indicated (from the same paraffin block if additional tissue is not available).

Reporting

For cancers, generally include a synoptic report, such as per College of American Pathologists (CAP) protocols at cap.org/protocols-and-guidelines.

  See also: General notes on reporting


General notes edit

Further reading:

Notes

  1. In such cases, step slices are taken rather than serial ones.
  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

Main page

References

  1. 1.0 1.1 . Cancer staging. National Cancer Institute. Retrieved on 4 January 2013.
  2. 2.0 2.1 . General oncology. Amboss. Retrieved on 2020-01-29.

Image sources