A Breast Excision That Missed the Formalin
A 62-year-old woman has a 1.8 cm ill-defined mass excised from the right breast at 14:10. The specimen reaches the gross room at 15:25 in a sterile container, wrapped in saline-moistened gauze - no formalin has been added. The pathologist is off-site until 17:00. The tech on duty has 10% neutral buffered formalin (NBF), 70% ethanol, and Bouin's on the shelf; the in-house immunohistochemistry lab runs ER, PR, and HER2 and closes at 17:30. The container label matches the requisition. The specimen has not been inked, oriented, or opened, and the surgeon's office is calling to ask whether the case can be signed out by Friday, three days from now.
1. What do you do in the next 60 minutes, and what must you avoid doing? Justify each action by the physics and chemistry of fixation.
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Do now (in this order):
- Record the clock. Excision 14:10, receipt 15:25 = 75 minutes of cold ischemia in a non-fixative medium. This number goes in the record and eventually the report; it cannot be recovered later.
- Open and slice the specimen. NBF penetrates at roughly 1 mm per hour, so an intact 1.8 cm mass would have a necrotic, autolyzed, unfixed center for the better part of a day. Serial slices at 3–4 mm give every cell a diffusion path of ~2 mm.
- Immerse in 10% NBF at ≥10:1 volume-to-tissue ratio, with the cassette/container labeled with the time fixation started.
- Notify the pathologist and ask whether inking is wanted before or after slicing, since inking decisions affect margin evaluation.
Do not:
- Use Bouin's. Picric acid is a coagulant fixative that degrades nucleic acids and masks antigens; it would jeopardize ER/PR/HER2 and any future molecular testing. It is also a hazardous material.
- Use 70% ethanol as a substitute. Alcohol is a precipitating fixative that produces different morphology and is outside the validation of an IHC assay validated on NBF-fixed tissue.
- Discard or 'rescue' the specimen. A suboptimal preanalytic interval is a documented variable, not grounds for rejection.
If the pathologist truly cannot reach the specimen within another hour, refrigerate at 2–8 °C to slow autolysis - and document that refrigeration occurred, since cold exposure is itself a preanalytic variable.
2. Is this specimen still acceptable for ER, PR, and HER2? What exactly goes in the report, and how would you handle a negative ER result?
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Acceptable - with a caveat, not a rejection. The widely used preanalytic standard for breast predictive markers calls for time to fixation of about 1 hour and NBF fixation of 6–72 hours. At 75 minutes in saline, this case exceeds the recommended time to fixation but remains within the range where testing is performed and interpreted.
Report language: state the time from excision to fixation, the fixative, and total fixation time. Something like: "Cold ischemia time 75 minutes (specimen transported in saline-moistened gauze); fixed in 10% NBF for X hours. Interpret with the knowledge that time to fixation exceeded 1 hour."
Reasoning about the result: prolonged warm/cold ischemia causes protein degradation and can produce false-negative ER and weak or absent PR; HER2 is somewhat more robust but can also be affected. So if ER returns 0%:
- Confirm the assay worked - the internal control (normal ducts and lobules) must show nuclear staining. If the internal control is also negative, the run is invalid and must be repeated, not reported as negative.
- If the internal control is positive but the tumor is 0%, report the negative result with the preanalytic caveat and note that a negative result in this setting may be unreliable; consider staining a deeper level or another block, and let the pathologist decide whether a repeat biopsy is warranted.
What you must not do is silently test and silently report - the whole value of the documentation is that the treating team can weigh the result.
3. Would your handling change if the mass had been 4 cm and arrived at 18:00? Explain your reasoning and state what is and is not still worth doing.
Read the worked answer
Yes, the risk profile changes substantially, though the actions are largely the same.
- A 4 cm mass arriving at 18:00 means ~3 h 50 min from excision to fixation and a much longer diffusion distance for fixative. Ischemic degradation of antigen and DNA is time- and temperature-dependent, so this specimen sits well outside the recommended window.
- Still do: slice at 3–5 mm, fix in 10% NBF at generous volume, record the times accurately, refrigerate if there is any further delay, and alert the pathologist.
- Still do not: switch to a harsher or faster fixative. A coagulant fixative does not 'make up for' ischemia - it adds a second, irreversible preanalytic injury and invalidates the IHC assay.
- What actually changes: the interpretive weight. A 0% ER in this scenario is much more likely to be a false negative, and the pathologist should be prompted to consider whether a repeat sample is needed before the patient is committed to endocrine therapy. If the case ends up being sent for molecular testing, note the ischemia time, because nucleic acid integrity is also affected.
The principle: you cannot undo a delay, but you can prevent a second one and you can make the delay visible to everyone downstream.