Pure sarcoma should be diagnosed only after thorough sectioning and with negative stains for p63, broad spectrum keratin and high molecular weight keratin
Spindled component may be positive for high molecular weight keratin or p63
Stromal component negative for high molecular weight keratin and p63
Epithelial component is malignant
Epithelial component is benign
Squamous differentiation may be present
No squamous differentiation
Nodular fasciitis is very rare in the breast and should be diagnosed only after thorough sectioning and with negative keratin stains (including high molecular weight keratin)
Fibromatosis is very rare in the breast and should be diagnosed only after thorough sectioning and with negative keratin stains (including high molecular weight keratin)
Pleomorphic adenoma is very rare in the breast and does not have infiltrating margins and the epithelial component is not malignant
Glandular component, if present, is histologically malignant, except in low grade spindle cell metaplastic carcinoma
Epithelial component is histologically bland
Stromal component may be bland or histologically malignant
Stroma is histologically bland
Stromal component may resemble a variety of sarcomas or low grade fibrous proliferation
Stroma shows myoepithelial differentiation only
Squamous differentiation may be present
No squamous differentiation
Clinical
Behavior is that of carcinoma rather than sarcoma
First metastases are to lymph nodes
Metastases are usually pure carcinoma
Recent studies have questioned this, finding sarcoma-like behavior (recurrence without nodal metastases but with hematologic metastases) in lesions with minimal or only focal evidence of typical carcinoma and bland fibrous stroma (spindle cell carcinoma)
5 year survival reported as 47-68%
Grading / Staging / Report
Grading
Bloom-Scarff-Richardson grading is not applicable to metaplastic carcinomas
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
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
Note extranodal extension
Report
Excisions: the following are important elements that must be addressed in the report for infiltrative breast carcinomas
Grade
Not generally applicable
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
Needle or core biopsies
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
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