Evaluation of suspected malignancies: Difference between revisions

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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.
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:
Visually, tumors and other suspected malignancies can broadly be classified as:
<gallery mode=packed>
<gallery mode=packed heights=220>
File:Non-proliferative versus proliferative colonic crypts.jpg|'''Gland-like tumors''' (image shows normal colonic crypt compared to an adenoma)
File:Non-proliferative versus proliferative colonic crypts.jpg|'''Gland-like tumors''', with tumor cells around lumina (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)
File:Histopathology of an ovarian fibroma.jpg|'''Spindle-cell tumors''', with elongated cells and/or nuclei
File:Histopathology of squamous-cell carcinoma of the lung.jpg|'''Epithelioid tumors''', typically having abundant eosinophilic cytoplasm.<ref name="pmid32316685">{{cite journal| author=Choi JH, Ro JY| title=Epithelioid Cutaneous Mesenchymal Neoplasms: A Practical Diagnostic Approach. | journal=Diagnostics (Basel) | year= 2020 | volume= 10 | issue= 4 | pages=  | pmid=32316685 | doi=10.3390/diagnostics10040233 | pmc=7236000 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=32316685  }} </ref>
File:Histopathology of Merkel-cell carcinoma with undifferentiated tumor cells.png|'''Undifferentiated tumors''', with few to no visual clues to their origin.
</gallery>
</gallery>


'''Gland-like tumors''' are mainly evaluated for cellular atypia, architectural dysplasia and invasion, and thereby classified into the following main categories:
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.
 
====Gland-like tumors====
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
*'''Adenomas''', which can range from mild to high-grade dysplastic, yet are generally confined within their anatomic layers, that is, they are not invasive.
*'''Adenomas''', which can range from mild to high-grade dysplastic, yet are generally confined within their anatomic layers, that is, they are not invasive.
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:*[[Endometrial adenocarcinoma]]
:*[[Endometrial adenocarcinoma]]


====Spindle-cell tumors====
For '''Spindle-cell tumors''', the shape of the nuclei is a clue to the diagnosis, with the following tendency:
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 both ends: True fibroblastic tumors
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Evaluate specifically by location when possible, such as [[spindle-cell tumors of the midgut]].
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.
====Undifferentiated tumor====
An initial panel of cytokeratin (CK), S100, vimentin and LCA (CD45) can be used.<ref name="pmid25427040">{{cite journal| author=Lin F, Liu H| title=Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin. | journal=Arch Pathol Lab Med | year= 2014 | volume= 138 | issue= 12 | pages= 1583-610 | pmid=25427040 | doi=10.5858/arpa.2014-0061-RA | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25427040  }} </ref>


====No tumor====
If a '''neoplasm has been ruled out''' for what clinically appeared like a tumor, seek a diagnosis that can be consistent with such a clinical finding. For example, for a breast biopsy of what appeared to look like a mass, and there is no neoplasia, look mainly for dense fibrosis, so that you can report that thereby explain the finding, rather than merely write "benign breast tissue".
If a '''neoplasm has been ruled out''' for what clinically appeared like a tumor, seek a diagnosis that can be consistent with such a clinical finding. For example, for a breast biopsy of what appeared to look like a mass, and there is no neoplasia, look mainly for dense fibrosis, so that you can report that thereby explain the finding, rather than merely write "benign breast tissue".