Evaluation of suspected malignancies: Difference between revisions

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===Gland-like tumors===
===Gland-like tumors===
[[File:Pap stain of adenocarcinoma in peritoneal fluid.png|thumb|250px|Typical features of adenocarcinomas on cytology (Pap stain). Vacuoles may be seen in both mucinous and serous tumors.]]
[[File:Histopathology of adenocarcinoma.png|thumb|250px|Typical features of adenocarcinomas. In reality, the appearance varies significantly from case to case. Vacuoles are more prominent in mucinous tumors, but can be seen in serous tumors as well.]]
Gland-like tumors are mainly evaluated for cellular atypia, architectural dysplasia and invasion, and thereby classified into the following main categories:
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
*'''Hyperplastic''' lesions, lacking significant atypia
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:*[[Esophageal adenocarcinoma]]
:*[[Esophageal adenocarcinoma]]
:*[[Endometrial adenocarcinoma]]
:*[[Endometrial adenocarcinoma]]
:*[[Pancreatic ductal adenocarcinoma]]
[[File:Well-, moderately and poorly differentiated colorectal adenocarcinoma.png|thumb|370px|Degree of differentiation, with example from a [[colorectal adenocarcinoma]].]]
Generally, adenocarcinomas are categorized by degree of '''differentiation''' as follows:
*Well differentiated: > 95% of tumor has glandular formations
*Moderately differentiated: 50 - 95% glandular
*Poorly differentiated: < 50% glandular
If '''[[Metastasis|metastatic]] adenocarcinoma''' seems to be the case (always consider this in at least [[lung adenocarcinoma]]), look at the history and radiology reports for a most likely primary. Generally, perform [[immunohistochemistry]] with one or two stains that are most typical for the suspected primary, and optionally add CK7 and CK20 as a broad screening. {{further|Metastasis}}


===Squamoid tumors===
===Squamoid tumors===
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===Further histopathologic subtyping and grading===
===Further histopathologic subtyping and grading===
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.
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, but generally much less so than staging.


{{Undifferentiated malignancy}}
{{Undifferentiated malignancy}}
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** M1: metastasis to distant organs (beyond regional lymph nodes)
** M1: metastasis to distant organs (beyond regional lymph nodes)
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[[File:Histopathology of a lymph node with metastatic invasive ductal carcinoma from the breast.jpg|thumb|220px|For positive lymph nodes, generally also note any '''extranodal extension''', and the size thereof.]]
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.
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. If a stage-defining finding is uncertain, generally fall back to the lower stage.


For the '''size''', the greatest dimension of the tumor is most important. Second and third dimensions (preferably at right angles compared to each other) are optional. Use the largest measure for each dimension. For example if one slide shows a tumor measuring 2.0 x 1.0 cm, and another slide shows the same tumor measuring 1.5 x 1.5 cm, then the tumor can be reported as measuring 2.0 x 1.5 cm. The third dimension can be estimated from gross measurement, or, if the tumor is entirely submitted, adding together the presumed thickness of each slice where tumor is found microscopically. For excisions with less than a centimeter of tumor, and where there has been a previous biopsy, consider looking at the size of tumor on the previous biopsy, which may be the largest measurement, and therefore the measurement of choice for staging.
For the '''size''', the greatest dimension of the tumor is most important. Second and third dimensions (preferably at right angles compared to each other) are optional. Use the largest measure for each dimension. For example if one slide shows a tumor measuring 2.0 x 1.0 cm, and another slide shows the same tumor measuring 1.5 x 1.5 cm, then the tumor can be reported as measuring 2.0 x 1.5 cm. The third dimension can be estimated from gross measurement, or, if the tumor is entirely submitted, adding together the presumed thickness of each slice where tumor is found microscopically. For excisions with less than a centimeter of tumor, and where there has been a previous biopsy, consider looking at the size of tumor on the previous biopsy, which may be the largest measurement, and therefore the measurement of choice for staging.
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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.
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>
</gallery>
[[File:Histopathology of pancreatic adenocarcinoma with treatment effect.jpg|thumb|Also note "treatment effect", seen as fibroelastotic tissue, here with scattered remaining tumor cells.]]


==Molecular workup==
==Molecular workup==
Send samples according to requirements and guidelines for each test. For molecular proliferation tests (other than [[immunohistochemistry]]) such as Ki67, avoid samples with previous biopsy site or inflammation (as these will cause a false high proliferation rate).
Ensure that any cancer undergoes reflex testing where applicable by local guidelines. When they are not applicable, a rule of thumb is to order individual genetic testing if there is a need to test up to 2 genetic targets, and to order genomic sequencing if more targets need genetic testing (not counting [[immunohistochemitry]] or other more easily performed tests).
 
When needing to '''send out''' tissue to an outside laboratory, follow their requirements and guidelines for each test. Generally, choose the tissue block with the greatest amount/area of the highest grade malignancy. For molecular proliferation tests (other than [[immunohistochemistry]]) such as Ki67, avoid samples with previous biopsy site or inflammation (as these will cause a false high proliferation rates). On the other hand, for next-generation sequencing, hemorrhage, necrosis and adipose tissue does not need to be minimized, as these contain only little genetic material.


==Reporting==
==Reporting==
[[File:Histopathology of pancreatic adenocarcinoma with treatment effect.jpg|thumb|Also note "treatment effect", seen as fibroelastotic tissue, here with scattered remaining tumor cells.]]
{{CAP}} If there is no CAP synoptic available for the cancer type at hand, attempt to find one in the latest AJCC Cancer Staging Manual (see the [[Secrets]] article), but make sure to use pathologic staging (with a p preceding the T, N or M) rather than clinical staging.
{{CAP}} If there is no CAP synoptic available for the cancer type at hand, attempt to find one in the latest AJCC Cancer Staging Manual (see the [[Secrets]] article), but make sure to use pathologic staging (with a p preceding the T, N or M) rather than clinical staging.


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