BMS Trimming

There is a lot of common ground between this page and Specimen types and tissue handling and it is planned to rationalise these two pages in a future version of the website. The page is incomplete and is the continuing subject of further 'work in progresss'.

    Principles for developing BMS Trimming of Breast Specimens

  1. Follow same basic protocol as laid down by the IBMS/RCPath
  2. Agree learning objectives
  3. Receive and discuss background educational material
  4. Observe Consultants and Trainees cutting specimens
  5. Supervised BMS trimming of less complex specimens
  6. Unsupervised trimming with preview and Consultant back-up/review
  7. Graduate through range of more complex specimens

Common breast specimens by level of cut-up complexity

Level 1

Level 2

Level 3

Level 4

General principles for breast specimen cut up

Level 1 specimens


See also reference in Common benign lesions"

  1. As a general rule if the lesion is < 40mm and the patient < 40yrs these lesions are not problematic
  2. For a lesion < 20mm take two representative blocks, if larger 1 block per 10mm as a rule of thumb
  3. Always sample areas that are focally different
  4. If clinically suspicious or previous suspicious core biopsy take additional blocks - up to 40mm block everything

Large fibroadenoma showing a smooth slightly lumpy surface, cut surface is unusual in that it looks more like a lipoma than a fibroadenoma

Large fibroadenoma (left) showing a smooth external contour, cut surface is variable in appearance (arrows) and requires thorough sampling.
Lesion on Right is a borderline phyllodes tumour. Note size and irregular, focally poorly demarcated margin.

Duct excisions (Microdochectomies)

Duct excisions are usually carried out for the investigation and treatment of single-duct nipple discharge.

Specimens are usually roughly conical 20 - 40 mm in length, 20 mm or so in maximum width often with a suture marking the (narrow) nipple end.

Serially slice the specimen across its long axis and block in its entirety with pieces in sequence from deepest (the base of the cone) to the most superficial. Do not ink the margins unless the specimen is oriented as a wide local excision with clips (see below).


  • Capsulotomies are rather ragged sac-like specimens approximately 100 mm maximum dimension that are removed when they contract around a breast implant.
  • They are removed primarily to improve the appearance of the breast but also to relieve discomfort.
  • The pathology revealed is usually limited to fibrous scarring +/- evidence of implant-contents leakage.
  • Take three or four blocks including the most ragged part of the specimen.

Sac-like capsulotomy specimen as received (left) and after bisection (right)

Casettes containing selected blocks from capsulotomy above

Section from capsule showing synovial metaplasia. Arrows point to entrapped silicone material. 'Mouse-over' for high power view of synovial metaplasia
High power (x40) view showing synovial metaplasia and foreign body giant cells

Foreign body giant cell reaction to silicone (left) and under polarised light (right)
Foreign body giant cell reaction to silicone Foreign body giant cell reaction to silicone (polarised light)

See also Case of the Month, April 2007

See also Image of the week 2009 - 2; FNA of silicone granuloma

Level 2 specimens

These specimens are covered at the present time in Specimen types and tissue handling.

Axillary Node Samples

Sentinel Node Biopsies

Level 3 specimens

Selected Wide Local Excisions (WLE)

These are oriented specimens at the more straightforwrd end of the spectrum. They would usually include:

  • Excisions of well centred carcinomas > 10mm

  • Excisions of core biopsy-indicated radial scars

Specimen orientation:

  • A specimen x ray should, ideally, accompany the specimen

  • The specimen is oriented according to local custom using the pre-agreed clip convention

  • We slice the specimen with the posterior margin flat on the trimming bench giving sagittal slices

  • The slices are examined for macroscopic lesions

Block selection:

  • Correlate macroscopic abnormalities with specimen x ray shadows where possible

  • Review block taking requirements with pathologist according to level of experience

  • Always be prepared to halt block-taking if difficulties arise and discuss case further with pathologist

  • A 'standard' set of blocks would include:

    • Anterior and posterior 'cruciates'

    • Four blocks each with one of the radial margins - see images below:

      • At least one to include lesion - depends on size and position of lesion

    • Extra blocks of the lesion if tissue available - with or without specified margin as appropriate

  • All margins to be inked - use more than one colour if more than one margin present on a block

    • 'Fix' ink by dipping block briefly in 5% acetic acid before placing in cassette

  • If you are taking a block for a margin without a macroscopic lesion try to ensure it is at least 5mm wide, prefrerably 10mm, so that a comment such as the following becomes possible when no tumour is present in the section:

    • 'Medial margin > 10mm'

  • Be prepared to be flexible about block-taking - it should be an intelligent process tailored to the individual specimen

Specimen X ray for WLE below
The clip convention used in this case is 1 clip anterior; 2 clips medial and
3 clips inferior
WLE left breast before (left) and after slicing(right)
Arrow points to single anterior clip (barely visible)

Centre slice (left) and cut up for blocks (right)
Arrow points to tumour - see also specimen X ray above

Level 3 Specimens

Axillary Node Clearances - See Specimen types and tissue handling

"Benign Mastectomies"

  • These are usually undertaken as a 'balancing' procedure when the patient has already had a mastectomy for cancer or for prophylaxis in higher risk patients

  • The specimen should be sliced and examined for macroscopic abnormalities which should be sampled.

  • If no macroscopic abnormality is seen then take one block per quadrant, a block from the central area and a block from the nipple.

  • If an abnormality is picked up in these blocks further blocks can be taken from the specimen

Mastectomies for large single tumours

  • The emphasis in these specimens is to sample the tumour well

  • There is published evidence that additional sampling of quadrants in these specimens adds little

  • Some surgeons insist on knowing the status of the posterior margin even when the tumour is far away

  • In skin-sparing and subcutaneous mastectomies it is logical to examine the anterior (and other relevant) margin(s) if the tumour is close or the procedure was carried out for DCIS.

  • Sample the axilla in the normal way

Mastectomies following a "failed" wide local excision

  • The general principle in handling these specimens is to sample adequately the cavity to determine whether there is any residual disease.

  • The rest of the specimen should be handled like any other mastectomy

Level 4 Specimens

Wide local excisions for small tumours

  • The secret for success here is a well fixed specimen.

  • Slice the wide local thinly and you should be able to spot a tumour down to 2 or 3mm.

  • If you can see the tumour, block the specimen as you would do so normally.

  • If you cannot, refer again to the specimen x ray which may help you and have a low threshold for putting the whole specimen through - as long as it is not too large

  • If the specimen is large, say part of an oncoplastic procedure, consider x raying the slices.

Wide local excisions for calcs

  • There are two principles here:

    1. If the specimen is small, block it all.

    2. If the specimen is larger, x ray the slices - it is the only way to be confident that you are blocking the right tissue

Mastectomies for calcs

  • Unless there is a gross abnormality such as a large area of comedo type DCIS my recommendation is to x ray the slices and take blocks accordingly

  • Any other approach runs the risk of mis-sampling the specimen.

Mastectomies for multiple lesions

  • A well fixed mastectomy will save you a lot of trouble here.

  • The specimen x ray may show tissue markers or calcs which at least lets you know what you are supposed to be sampling.

  • Reviewing the laboratory computer record will often give you more information than is supplied on the request form.

  • In the end, if you cannot see the tissue markers or all the tumours identified pre-operatively, you will need to x ray the slices and take it from there.

Return to top of page