General Guidelines:

Nuclear score 1: Nuclei are small to medium-sized, relatively uniform in size and shape, and lacking clumped chromatin or prominent nucleoli. Nuclei may have small, inconspicuous nucleoli. Uniformity of size and shape are the most important features.

Nuclear score 2: Nuclei are medium to large in size but exhibit only moderate variability in size, shape and intensity and pattern of staining. Nucleoli may be quite prominent as long as the nuclei are relatively monotonous in appearance. Nucleoli with irregular outlines, giant or "macronucleoli" are absent. Bizarre giant cells are absent.

Nuclear score 3: Nuclei are large and vesicular and/or contain coarse clumps of chromatin. There is considerable variation in the size and shape of nuclei. Typically, nucleoli are very large, often multiple and may have irregular outlines. Giant nuclei, polylobated nuclei and multinucleate tumour giant cells may be present. Karyorrhexis, karyolysis and pyknosis of nuclei are often encountered.

Note: The above descriptions are given as guidelines, which may be supplemented by study of illustrations of the different nuclear grades in the references, cited below. Furthermore, since there is a morphological continuum in the nuclear appearance in breast carcinomas, the extremes of the spectrum are easily recognised but, in some cases, the scoring of nuclei is to some extent subjective and differences of interpretation between pathologists are to be expected. It must be stressed that it is impossible to assign a nuclear score based on the frozen section or post-frozen paraffin embedded material.

The assessment of tubular differentiation or tubule formation applies to the neoplasm overall and requires examination of several sections at scanning magnification. A reliable tubular score cannot be assigned when only needle biopsies or small pieces of the tumour are examined.

Tubule score 1: >75% of the neoplasm is composed of tubular structures with visible lumina. Solid trabecula, vacuolated single cells, alveolar nests and solid sheets of cells comprise less than 25% of the tumour.

Tubule score 2: 10-75% of the tumour has a tubular pattern.

Tubule score 3: <10% tubule formation.

The mitosis score is assessed in the peripheral areas of the neoplasm and not the sclerotic central zone. The neoplasm is scanned at intermediate magnification to determine the area in which mitoses are most abundant (usually areas of poor tubule formation where cells are arranged in sheets or large nests). Only definite mitotic figures are counted with care to avoid including pyknotic nuclei in the count. Although the Nottingham grading system uses a scoring system based on the number of mitoses per 10HPF's, the Oncologic Standards Committee considers that a mitotic count per square millimetre is most accurate. Mitoses are only counted in the invasive component of the lesion.

Score 1: <4 mitoses per square mm.

Score 2: 4-7 mitoses per square mm.

Score 3: >7 mitoses per square mm.

Alternatively the number of mitoses in 10 high power fields (HPFs) is counted. Using a Nikon Labophot microscope with a 40X objective lens (i.e. X400) and a field surface area of 0.152mm2, the scores are as follows :-

Score 1: 0-5 mitoses

Score 2: 6-10 mitoses

Score 3: >10 mitoses

In practice, Contesso's method of scoring of mitoses is quicker and easier to perform especially on small biopsies (e.g. Core biopsies). At least 20HPF's of the same area as stated above are assessed and scored as follows :-

Score 1: No field contains more than 1 mitosis.

Score 2: Two mitoses present in any one HPF.

Score 3: Three or more mitoses present in any one HPF.

The scores for the three separate parameters (tubules, nuclei and mitoses) are summated and the overall grade of the neoplasm is determined as follows :-

Grade 1: 3-5 points.

Grade 2: 6-7 points.

Grade 3: 8 or 9 points.

The following patterns of DCIS are recognized:

Low Grade (Grade 1): Grade 1 or 2 nuclei and no zonal necrosis.

Intermediate grade (Grade 2): Grade 1 or 2 nuclei with zonal necrosis

High grade (Grade 3): Grade 3 nuclei with or without necrosis

Quantitation: In addition to the maximal linear size of the DCIS, a rough estimate of the volume of DCIS relative to the overall tumour should be given as a percentage. "Extensive intraduct component (EIC)" is used to qualify invasive carcinomas with DCIS, which may take two forms as follows :

This assessment is important because EIC carcinomas treated with breast conservation have a higher risk of local recurrence within the breast unless the margins are well clear.¹⁵

In general, it is possible to grade lobular carcinoma. Usually, classical lobular carcinoma will attain a total score of 5 (tubules 3; nuclei 1; mitoses 1) giving the tumour an overall grade 1. Although some of the data are somewhat inconclusive, histological variants of lobular carcinoma are thought to differ in their degree of aggressiveness as follows:

Only invasion of lymphatics beyond the advancing edge of the tumour is important.

If in doubt call it negative.

Please state if there is extensive lymphatic/vascular invasion (>10 lymphatics involved).

Large calibre, thick-walled blood vessels containing tumour emboli either within the tumour in the surrounding tissue are included.

Neural invasion has been shown not to be of prognostic significance in most studies. This is confirmed in a recent analysis of BC Cancer data.

Tumour cells must be outside the nodal capsule.

Please state if "minimal" extra nodal spread (<1mm from capsule) or extensive infiltration of perinodal tissues with "matting" of nodes.

Breast markers on invasive carcinoma should be done on the core biopsy sample where relevant. Only if the results appear incongruous with the histology, should the markers be repeated on the excision specimen.

DCIS should be stained for ER in the excision specimen. PR and Her2-neu status of DCIS is not relevant for management of the patient.

1) Estrogen Receptors

Please select a block containing invasive carcinoma and normal breast tissue if possible.

Immunostains are graded subjectively on a scale 0-3+.

0 :- Negative nuclear staining; positive internal control staining. Allred scores 0(1,2)

1+ :- Allred scores 3-4

2+ :- Allred scores 5 and 6

3+ :- Allred scores 7 and 8

Allred Score: Percentage of nuclei staining + Intensity + Total score