scholarly journals HER2 Immunohistochemistry in Invasive Micropapillary Breast Carcinoma: Complete Assessment of an Incomplete Pattern

2020 ◽  
Author(s):  
Marjorie Perron ◽  
Hannah Y. Wen ◽  
Matthew G. Hanna ◽  
Edi Brogi ◽  
Dara S. Ross
Keyword(s):  
Breast Carcinoma ◽  
Staining Pattern ◽  
Her2 Status ◽  
Invasive Micropapillary Carcinoma ◽  
Receptor Profile ◽  
Detailed Assessment ◽  
Alternative Testing ◽  
American Society ◽  
Micropapillary Component

Context.— Invasive micropapillary carcinoma (IMPC) is a rare variant of breast carcinoma, composed of avascular morula-like tumor clusters surrounded by stromal spaces, which can affect the HER2 immunohistochemical (IHC) staining pattern. The 2013 American Society of Clinical Oncology/College of American Pathologists HER2 testing guideline (ASCO/CAP) suggests moderate to intense but incomplete (basolateral) staining be considered equivocal. Objectives.— To perform a detailed assessment of HER2 IHC staining patterns in IMPC. Design.— Hematoxylin-eosin and HER2 IHC slides were retrospectively reviewed to assess the morphology and HER2 IHC characteristics of IMPC. The 2018 ASCO/CAP guideline was applied. Results.— The cohort consisted of 187 IMPCs from 181 patients with median age of 58 years. Homogeneous (≥90%) micropapillary component was found in 40% (75 of 187) of cases. Receptor profile was as follows: 75% (140 of 187) ER+ HER2−, 19% (37 of 187) ER+ HER2+, 4% (7 of 187) ER− HER2+, and 2% (3 of 187) ER− HER2−. Of 26 cases with HER2 IHC 3+, 65% (17 of 26) showed a basolateral staining pattern with strong intensity. HER2 fluorescence in situ hybridization (FISH) showed amplification in 26% (17 of 66) of HER2 IHC equivocal cases: 76% (13 of 17) showed basolateral staining pattern and 24% (4 of 17) complete staining, with weak to moderate (2), moderate (14), or moderate to strong (1) intensity. Conclusions.— The most frequent staining pattern was basolateral, seen in 49% of cases, including 65% HER2 IHC positive and 76% HER2 IHC equivocal/FISH amplified. If a basolateral pattern and weak to moderate staining is observed in IMPC, alternative testing should be performed to confirm the HER2 status.

scholarly journals Quantitative Impact of the 2018 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) Practice Guideline Update on Human Epidermal Growth Factor Receptor 2 (HER2) Testing in Breast Cancer: A Systematic Analysis

2020 ◽  
Author(s):  
Christina H. Wei ◽  
Lino Garcia ◽  
Joyce Murata-Collins ◽  
Daniel Schmolze ◽  
Sophia Apple
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
In Situ Hybridization ◽  
Growth Factor ◽  
Fluorescence In Situ Hybridization ◽  
Growth Factor Receptor ◽  
Her2 Status ◽  
Epidermal Growth ◽  
American Society ◽  
Quantitative Impact

Context.— The global impact of the new 2018 American Society of Clinical Oncology/College of American Pathologists human epidermal growth factor receptor 2 (HER2) practice guideline update on the overall HER2 status designation, compared with the prior 2013 iteration, is unknown. Objectives.— To report the quantitative impact of the new guideline on HER2 status distribution. Design.— The analysis comprised a retrospective cohort of patients from the author's institution, combined with other peer-reviewed publications that assessed the impact of the 2018 guideline in relation to the 2013 guideline. Results.— Our study revealed that the new guideline led to an average 9% reclassification rate for the overall HER2 status, with a net gain in overall HER2 negative designation. This is largely due to reclassification of the equivocal (Group 4) groups. Unexpectedly, infrequent but consistent discordance between Group 1/5 and fluorescence in situ hybridization results are observed across studies (1.8%; 73 of 3965 cases where fluorescence in situ hybridization and immunohistochemistry are both reported). Conclusions.— Early clinical recognition of these resultant changes, including emerging issues of tumor heterogeneity, and potential discordance between immunohistochemistry to fluorescence in situ hybridization, is important for accurate clinical assessment of individual HER2 test results.

Tubulopapillary Carcinoma: An Aggressive Variant of Invasive Breast Carcinoma With a Micropapillary DCIS-Like Morphology

2019 ◽  
Vol 28 (5) ◽  
pp. 536-540
Author(s):  
Claudio Guerrieri ◽  
Rachel Hudacko
Keyword(s):  
Breast Carcinoma ◽  
Invasive Carcinoma ◽  
Ductal Carcinoma ◽  
Myoepithelial Cells ◽  
Invasive Breast Carcinoma ◽  
Axillary Lymph Nodes ◽  
Axillary Lymph ◽  
Invasive Micropapillary Carcinoma ◽  
Serous Papillary Carcinoma

Tubulopapillary carcinoma is a recently described variant of breast carcinoma characterized by a proliferation of elongated and anastomosing tubular glands exhibiting intraluminal micropapillary and sometimes papillary epithelial projections. We have recently encountered a patient with invasive breast carcinoma displaying a prominent tubulopapillary component. The histomorphology in our case had an uncanny resemblance to micropapillary ductal carcinoma in situ, but the invasive nature of the glands was confirmed not only by the lack of myoepithelial cells but also by the presence of identical metastatic foci within ipsilateral axillary lymph nodes. This case was made all the more intricate by the simultaneous presence of invasive micropapillary carcinoma in the opposite breast and a carcinosarcoma of the uterus with a serous papillary carcinoma component. As noted in the only prior report on tubulopapillary carcinoma of the breast, our case confirms the aggressive nature of this form of invasive carcinoma, the histological features of which appear to be easily identifiable and reproducible.

scholarly journals Impact of the 2018 ASCO/CAP HER2 Guideline Focused Update

2019 ◽  
Vol 152 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Adlin M Gordian-Arroyo ◽  
Debra L Zynger ◽  
Gary H Tozbikian
Keyword(s):  
Invasive Carcinoma ◽  
Growth Factor Receptor ◽  
Her2 Status ◽  
Her2 Positive ◽  
Positive Rate ◽  
Epidermal Growth ◽  
American Society ◽  
The Impact ◽  
Positive Breast Cancer

ABSTRACT Objectives The 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) human epidermal growth factor receptor 2 (HER2) guideline focused update revises the HER2 scoring criteria. We evaluated the impact on HER2 rates in breast carcinoma diagnosed at our center. Methods In a retrospective series of breast core biopsies with invasive carcinoma diagnosed between 2014 and 2017 (n = 1,350), HER2 status was classified according to 2013 and 2018 ASCO/CAP guidelines and changes in HER2 status identified. Results The 2018 guidelines reclassified the HER2 status of 6% of patients. Most changed from HER2 equivocal status (equivocal by immunohistochemistry and fluorescence in situ hybridization under the 2013 guidelines) to HER2-negative status (2018 guidelines). The HER2-positive rate decreased by 0.4%. Conclusions The 2018 guidelines decrease the rate of HER2 equivocal and positive breast cancer and reduce repeat HER2 testing on excision specimens. Approximately 0.4% of patients will become newly ineligible for anti-HER2 therapy.

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