: Most earlier reports of mucocele‐like lesions (MLL) of the breast have dealt with symptomatic cases in premenopausal women or lesions found incidentally in breast biopsies performed for other ...reasons. The diagnosis of this lesion has special challenges in the setting of mammographic screening for breast cancer because the imaging characteristics of MLL may mimic those of ductal carcinoma in situ (DCIS), while mucinous carcinoma enters the differential diagnosis on cytologic grounds. This report focuses on our experience with MLLs detected during screening mammography. Cases with MLL as the final histologic diagnosis in our database during January 1992–June 2000 are included. The results of clinical, imaging, cytologic, core biopsy, and histologic examination of these lesions are recorded. The relevant literature is reviewed. Twenty‐six cases were found, with a mean patient age of 57.5 years. Microcalcifications were the dominant radiologic abnormality in 22 cases (84.6%). Imaging was considered suspicious or almost certainly malignant in 17 cases (65.4%). Cytology was classified as atypical or suspicious in 17 cases (70.9%). However, open biopsy showed mostly benign changes, including atypical ductal hyperplasia (ADH) in five cases (19.2%). In one case, ADH merged with a 3–4 mm focus of low‐grade DCIS. This, the largest series focusing purely on screen‐detected MLL, suggests that the combination of clinical, imaging, and cytologic features of screen‐detected MLL are different from those of mucinous carcinoma, symptomatic MLL, or incidental MLL. Correlating the cytomorphology of mucinous lesions of the breast with their mammographic appearance may permit more precise preoperative diagnosis.
Background
Technical advances have improved the detection of small mammographic lesions. In the context of mammographic screening, accurate sampling of these lesions by percutaneous biopsy is crucial ...in limiting diagnostic surgical biopsies, many of which show benign results.
Methods
Women undergoing core biopsy between January 1997 and December 2007 for <10‐mm lesions are included. Patient demographics, imaging features and final histology were tabulated. Performance indices were evaluated.
Results
This audit includes 803 lesions <10 mm. Based on core histology, 345 women (43.0%) were immediately cleared of malignancy and 300 (37.4%) were referred for definitive cancer treatment. A further 157 women (19.6%) required diagnostic surgical biopsy because of indefinite or inadequate core results or radiological‐pathological discordance, and one woman (0.1%) needed further imaging in 12 months. The open biopsies were malignant in 46 (29.3%) cases. The positive predictive value of malignant core biopsy was 100%. The negative predictive value for benign core results was 97.7%, and the false‐negative rate was 2.6%. The lesion could not be visualized after core biopsy in 5.1% of women and in 4.0% of women with malignant core biopsies excision specimens did not contain residual malignancy. Excessive delays in surgery because of complications of core biopsy were not reported.
Conclusion
Even at this small size range, core biopsy evaluation of screen‐detected breast lesions is highly effective and accurate. A lesion miss rate of 3.1% and under‐representation of lesions on core samples highlight the continued need for multidisciplinary collaboration and selective use of diagnostic surgical biopsy.
Abstract Background The mammographic grading system used by BreastScreen Australia accredited programs requires needle biopsy of lesions with indeterminate features (grade 3). We wished to determine ...the predictors of malignancy for these common lesions, so as to reduce surgery for benign lesions. Design Grade 3 masses assessed between Jan 1996–Dec 2005 are included. New or changing lesions were identified through film review. Imaging, demographic and final outcome data were tabulated. Statistical analysis was performed to determine the predictors of malignancy. Results 1181 lesions, including 623 new or changing masses are assessed. Of these 98 (8.3%) were malignant. Malignancy was found in 3% first round masses versus 13% of new or changing lesions. Withholding needle biopsy results, interval change (OR 2.85, p = 0.0001), increasing age ( p = 0.0001) and diameter were independent predictors of malignancy, lesion diameter having an inverse relationship with malignancy. Once needle biopsy results were included, this parameter became the sole predictor of malignancy as other factors lost significance in a multivariate model. Conclusion Surgical biopsy is not indicated in well-sampled grade 3 masses with benign needle biopsy results. Surgery is valuable for diagnosis or treatment of the remaining such masses without benign needle biopsy results.
A case is reported in which a fibrosarcoma developed 20 years after irradiation of a pituitary chromophobe adenoma. This rare lesion, like most of the other documented postirradiation pituitary ...sarcomas, was a combination of fibrosarcoma and pituitary adenoma. These lesions tend to behave in a characteristic fashion, with onset after a long latent interval following irradiation, growth to a large size, and failure to metastasize.
Hydrogen Epoch of Reionization Array (HERA) DeBoer, David R.; Parsons, Aaron R.; Aguirre, James E. ...
Publications of the Astronomical Society of the Pacific,
04/2017, Volume:
129, Issue:
974
Journal Article
Peer reviewed
Open access
The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization (z = 6-12), and to ...explore earlier epochs of our Cosmic Dawn (z ∼ 30). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14 m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.
Abstract
We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data (∼36 hr of integration) from Phase I of the Hydrogen Epoch of ...Reionization Array (HERA). The Phase I data show evidence for systematics that can be largely suppressed with systematic models down to a dynamic range of ∼10
9
with respect to the peak foreground power. This yields a 95% confidence upper limit on the 21 cm power spectrum of
Δ
21
2
≤
(
30.76
)
2
mK
2
at
k
= 0.192
h
Mpc
−1
at
z
= 7.9, and also
Δ
21
2
≤
(
95.74
)
2
mK
2
at
k
= 0.256
h
Mpc
−1
at
z
= 10.4. At
z
= 7.9, these limits are the most sensitive to date by over an order of magnitude. While we find evidence for residual systematics at low line-of-sight Fourier
k
∥
modes, at high
k
∥
modes we find our data to be largely consistent with thermal noise, an indicator that the system could benefit from deeper integrations. The observed systematics could be due to radio frequency interference, cable subreflections, or residual instrumental cross-coupling, and warrant further study. This analysis emphasizes algorithms that have minimal inherent signal loss, although we do perform a careful accounting in a companion paper of the small forms of loss or bias associated with the pipeline. Overall, these results are a promising first step in the development of a tuned, instrument-specific analysis pipeline for HERA, particularly as Phase II construction is completed en route to reaching the full sensitivity of the experiment.
Abstract
Recently, the Hydrogen Epoch of Reionization Array (HERA) has produced the experiment’s first upper limits on the power spectrum of 21 cm fluctuations at
z
∼ 8 and 10. Here, we use several ...independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization from these limits. We find that the IGM must have been heated above the adiabatic-cooling threshold by
z
∼ 8, independent of uncertainties about IGM ionization and the radio background. Combining HERA limits with complementary observations constrains the spin temperature of the
z
∼ 8 neutral IGM to 27 K
〈
T
¯
S
〉
630 K (2.3 K
〈
T
¯
S
〉
640 K) at 68% (95%) confidence. They therefore also place a lower bound on X-ray heating, a previously unconstrained aspects of early galaxies. For example, if the cosmic microwave background dominates the
z
∼ 8 radio background, the new HERA limits imply that the first galaxies produced X-rays more efficiently than local ones. The
z
∼ 10 limits require even earlier heating if dark-matter interactions cool the hydrogen gas. If an extra radio background is produced by galaxies, we rule out (at 95% confidence) the combination of high radio and low X-ray luminosities of
L
r
,
ν
/SFR > 4 × 10
24
W Hz
−1
M
⊙
−
1
yr and
L
X
/SFR < 7.6 × 10
39
erg s
−1
M
⊙
−
1
yr. The new HERA upper limits neither support nor disfavor a cosmological interpretation of the recent Experiment to Detect the Global EOR Signature (EDGES) measurement. The framework described here provides a foundation for the interpretation of future HERA results.
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