Pure Mucinous Carcinoma of the Breast
Grading / Staging / Report
Grading
- Usually low grade cytology but all degrees of atypia may be found
- Bloom-Scarff-Richardson grading scheme is most widely used
- Total score and each of the three components should be reported
- Based on invasive area only
| Tubule formation | Score |
|---|---|
| >75% tubules | 1 |
| 10-75% tubules | 2 |
| <10% tubules | 3 |
| Nuclear pleomorphism (most anaplastic area) | Score |
|---|---|
| Small, regular, uniform nuclei, uniform chromatin | 1 |
| Moderate varibility in size and shape, vesicular, with visible nucleoli | 2 |
| Marked variation, vesicular, often with multiple nucleoli | 3 |
| Mitotic figure count per 10 40x fields (depends on area of field, see key below) | Score | ||||
|---|---|---|---|---|---|
| 0.096 mm2 | 0.12 mm2 | 0.16 mm2 | 0.27 mm2 | 0.31 mm2 | |
| 0-3 | 0-4 | 0-5 | 0-9 | 0-11 | 1 |
| 4-7 | 5-8 | 6-10 | 10-19 | 12-22 | 2 |
| >7 | >8 | >10 | >19 | >22 | 3 |
- Olympus BX50, BX40 or BH2 or AO or Nikon with 15x eyepiece: 0.096 mm2
- AO with 10x eyepiece: 0.12 mm2
- Nikon or Olympus with 10x eyepiece: 0.16 mm2
- Leitz Ortholux: 0.27 mm2
- Leitz Diaplan: 0.31 mm2
- Mitotic count figures based on original data presented for Leitz Ortholux by Elston and Ellis 1991, with modifications based on pubished and measured areas of view
- Evaluate regions of most active growth, usually in cellular areas at periphery
- We employ strict criteria for identification of mitotic figures
| Sum of above three components | Overall grade |
|---|---|
| 3-5 points | Grade I (well differentiated) |
| 6-7 points | Grade II (moderately differentiated) |
| 8-9 points | Grade III (poorly differentiated) |
Staging
- TNM staging is the most widely used scheme for breast carcinomas but is not universally employed
- Critical staging criteria for regional lymph nodes
- Isolated tumor cell clusters
- Usually identified by immunohistochemistry
- Term also applies if cells identified by close examination of H&E stain
- No cluster may be greater than 0.2 mm
- Multiple such clusters may be present in the same or other nodes
- Usually identified by immunohistochemistry
- Micrometastasis
- Greater than 0.2 mm, none greater than 2.0 mm
- Metastasis
- At least one carcinoma focus over 2.0 mm
- If one node qualifies as >2.0 mm, count all other nodes even with smaller foci as involved
- Critical numbers of involved nodes: 1-3, 4-9 and 10 and over
- At least one carcinoma focus over 2.0 mm
- Note extranodal extension
- Isolated tumor cell clusters
Report
- In the context of mucinous carcinoma, the presence of mucin in a margin constitutes involvement by carcinoma
- Excisions: the following are important elements that must be addressed in the report for infiltrative breast carcinomas
- Grade
- Total score and individual components
- Size of neoplasm
- Give 3 dimensions or greatest dimension
- Critical cutoffs occur at 0.5 cm and at 2 cm
- Margins of resection
- Measure and report the actual distance of both invasive and in situ carcinoma
- Angiolymphatic invasion
- Indicate if confined to tumor mass, outside tumor mass or in dermis
- (Extensive DCIS is not currently felt to be a significant predictor of behavior)
- Results of special studies performed for diagnosis
- Results of prognostic special studies performed
- ER, PR, Proliferation marker, Her2neu
- If studies were performed on a prior specimen, refer to that report and give results
- Grade
- Needle or core biopsies
- Provisional grade may be given but may defer to excision for definitive grade
- Presence of absence of angiolymphatic invasion
- Results of special studies performed for diagnosis
- Results of prognostic special studies if performed
- ER, PR, Proliferation marker, Her2neu
- State if studies are deferred for a later excision specimen
- Regional lymph nodes
- Report findings as described above
