View source for Gross processing

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|author1=[[User:Mikael Häggström|Mikael Häggström]]
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Following are general notes on selection and trimming in pathology.
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==Priority==
{|class=wikitable align=right
|+ Priority
| 
1. More invasive intraoperative consultations<br>(such as open surgery)<br>
2. Less invasive intraoperative consultations<br>(such as skins)<br>
3. Fresh lymph nodes<br>
4. Fresh breast tissue (should be in<br>formalin within an hour from surgery)<br>
5. Other fresh tissue<br>
6. Tissue in formalin
|}
For '''prioritizing''' when you have more than one thing ongoing at the same time, the list at right can be used. 

==Fresh specimens==
The initial processing of fresh specimens is also termed '''triaging'''.

*For intraoperative consults including frozen sectioning, see separate article on '''[[Emergent pathology]]'''.

When triaging a specimen, the measurements are most important as these may change after fixation. Other descriptions can generally be made after the specimen is fixed.

*See also separate article on '''[[fixation]]''', including what specimens should not immediately be put in formalin (mostly [[tophus]], [[lymph node]]s and [[products of conception]]).

==Before cutting==
*Confirm that the patient '''identity''' on the specimen container matches the identity that will be applied to the gross description and cassettes. {{Finding-begin}}If the referral or requisition form is available, confirm the patient identity on that one as well.{{Finding-end}}
[[File:Right or left renal stone.jpg|thumb|160px|For unclear or potentially ambiguous handwriting (here "Right" or "Left" renal stone), look at the referral or requisition form {{Comprehensive-begin}}and the medical record if available{{Comprehensive-end}}.]]
*{{Moderate-begin}}Check for any '''discrepancy''' between the specimen description on the container and on the referral or requisition form, such as left versus right.{{Moderate-end}}
*Don't omit any piece in the container, such as ones '''hidden''' in wraps.
*Generally '''measure''' in 3 dimensions, or in volume, but the greatest dimension is generally enough for specimens less than 0.4 cm.
*Generally '''weigh''' entire organs, after having any attached tissue trimmed away if feasible.
*{{Moderate-begin}}Note the color of the sample, even when unremarkable, but do not linger on deciding it.{{Moderate-end}}<ref group=note>The color of gross specimens generally has very limited clinical significance.</ref>
*Generally, use '''[[inking]]''' for resection margins where '''[[tumor]]''' radicality is important. {{further|inking|linebreak=no}}
*{{Moderate-begin}}On fatty or greasy surfaces, apply '''vinegar''' to emulsify and remove the fat, dry the specimen and then ink. Otherwise, vinegar can be used either before or after inking to "dry" it.{{Moderate-end}}
*{{Moderate-begin}}Preferably '''photograph''' or make a drawing where slices have been taken.{{Moderate-end}}<ref name=Roychowdhury>{{cite web|url=https://www.pathologyoutlines.com/topic/breastmalignantgrossing.html|title=Grossing (histologic sampling) of breast lesions|author=Monika Roychowdhury|website=Pathologyoutlines.com}} Topic Completed: 1 August 2012. Revised: 19 September 2019</ref>
*Remove any surgical '''stitches''' from samples before microtomy.
*{{Moderate-begin}}At least for larger samples, consider looking for '''medical imaging''' or '''biopsy reports''' in order to better guide the process.{{Moderate-end}}<ref name=chicago>{{cite web|url=https://voices.uchicago.edu/grosspathology/head-neck/thyroid/#primary-column|title=Gross Pathology Manual By The University of Chicago Department of Pathology}} Updated 2-14-19 NAC.</ref>
*Fix '''bone''' in formalin prior to decalcification. Use reminders so not to forget bone that is decalcifying.
*'''Plan''' in which order to cut different parts so as to be able to take all relevant sections. Generally sample relevant surgical margins and smaller parts first, as these may be harder to find or even be fragmented later on.

==Cutting==
*When cutting with the longer knives, try to cut in '''one stroke''' - do not use like a saw (continuous back and forth)
*Generally, strive to make slices perpendicular to visible '''interfaces''' of relevant tissues.
*Generelly dissect and inspect the '''entire''' specimen, while keeping relevant parts intact enough for presentation to seniors and/or maintaining orientation.
*'''Trim''' tissues for microscopy examination to a thickness of maximum 3-4 mm.<ref group=note>Thicker slices may not become adequately fixated in formalin.</ref>

===Perpendicular versus en face sections===
[[File:Perpendicular versus en face.jpg|thumb|220px|Perpendicular and ''en face'' sections]]
Two major types of sections in gross processing are perpendicular and ''en face'' sections:
*'''Perpendicular sections''' allow for measurement of the distance between a lesion and the surgical margin.
*'''''En face''''' means that the section is ''tangential'' to the region of interest (such as a lesion) of a specimen. It does not in itself specify whether subsequent microtomy of the slice should be performed on the peripheral or proximal surface of the slice (the peripheral surface of an ''en face'' section is closer to being the ''true'' margin, whereas the proximal surface generally displays more area and therefore generally has greater sensitivity in showing pathology, also compared to perpendicular sections).
:*A '''shaved''' section is a superficial ''en face'' slice that contains the entire surface of the segment.

==Tissue selection==
When sampling sections to submit for microscopic examination, whenever you sample from something that looks abnormal, generally try to also sample from the same type of tissue that looks '''normal'''.<ref group=note>Normal sections from the same tissue helps identifying what is histologically abnormal in the grossly abnormal tissue, versus normal individual variations.</ref>

==Biopsy wraps, bags and sponges==
[[File:Biopsy wrap, biopsy sponge and biopsy bag.jpg|thumb|Items used for submitting specimens: (Biopsy) wrap, (biopsy) sponge, (tissue processing) cassette and (biopsy) bag.]]
Put the following types of specimens in '''bags''':
*'''Tiny''' specimens that need to be poured out from their containers.
*'''Bloody''' specimens such as endometrial curettages or [[products of conception]]. For products of conception, chorionic villi may otherwise contaminate other specimens. Bloody specimens may stick to wraps, so generally avoid that situation.
*'''Friable''' tissue such as urinary bladder biopsies.

Put the following types of specimens in '''bags, wraps or sponges''':
*Other '''tiny''' specimens
*{{Comprehensive-begin}}Any '''small''' piece of tissue where there is no leftover specimen to retake sections, since tissues occasionally get lost from cassettes, and the absence of a wrap, sponge or bag in the cassette of such cases points towards a mistake made at gross processing.{{Comprehensive-end}}
Specimens must be fixed enough to be put on sponges.

==H&E staining urgency==
{{Moderate-begin}}Even in departments where other staff are primarily responsible for determining the urgency of H&E staining of each specimen, still double-check that it is correct if you can, such as by cassette color.{{Moderate-end}} A major indication for rushing cases through H&E staining is a high risk of cancer, especially where '''immunohistochemistry''' staining will likely be performed, and the decision and types of staining will be determined by the standard H&E stain. Tissues that are generally rushed are:
*'''[[Brain]]''' biopsy.
*'''[[Lung]]''' biopsy.
*'''[[Breast]]''' needle biopsy.
*Biopsy from known '''[[tumor]]''' tissue.
*Suspected malignant '''[[lymph nodes]]''', including lymphoma. However, these are generally not urgent when submitted together with a tumor, except mainly for the following (which are generally urgent):
:*Pelvic sentinel lymph nodes 
:*Sentinel lymph nodes from known [[invasive lobular carcinoma]] (but not [[invasive ductal carcinoma]])
In both these cases, the cases are rushed so that immunohistochemistry can be performed if a metastasis is not readily detected on standard H&E slides, so that it is available by the time the rest of the slides are out. Immunohistochemistry in these cases can detect micrometastases that are not readily visible on H&E stain, but are evident on cytokeratin AE1/AE3. However, if the lab stains such cases regardless of whether H&E stain shows a metastasis or not, then they do not need to be rushed.

==Marking cassettes==
Use only hard pencil (or specially purchased histology markers), as marks made with pens, Sharpie markers, or scientific freezer-safe markers can get dissolved in tissue processing.<ref>{{cite web|url=https://unclineberger.org/pathologyservices/instructions/histopathology-services/|title=Histopathology Services|website=UNC School of Medicine|accessdate=2021-11-15}}</ref>
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==By organ or organ system==
*[[Gross processing of skin excisions]]
{{General notes}}
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