You are here

Ira J. Bleiweiss, MD

Professor of Pathology and Laboratory Medicine
Director, Breast Pathology Subspecialty Service
University of Pennsylvania, Perelman School of Medicine
Philadelphia, Pennsylvania

Current Research

  • Evaluate mammography screening technologies on the frequency of pre-malignant diagnoses.
  • A training program is implemented to evaluate the frequency of pre-malignant breast diagnoses with 2-D vs. 3-D mammography.
  • Results from this study will provide insight into which when to use 2-D and when to use 3-D mammography. 

Early pre-malignant changes in the breast can be a sign of increased risk of breast cancer and alert a patient and her physician regarding the need for more frequent breast cancer screening. 2-D digital mammography has become the new standard for breast cancer screening, but the more advanced 3-D tomosynthesis is assumed to be better – though it is not as widely available as 2-D technology. Dr. Bleiweiss is leading a study to compare the diagnoses from each technology to determine if one is better than the other. 

Full Research Summary

In the last several decades mammography has progressed rapidly from analog to digital and with these advances the precision of diagnosis of benign, risk-associated lesions has increased. These include non-invasive lesions, such as atypical duct hyperplasia, radial scar, intraductal papilloma, atypical lobular hyperplasia, and in situ lobular carcinoma.  

While 2D-digital mammography has been in use for at least a decade, 3D-digital breast tomosynthesis has been utilized for a shorter timeframe and because of its advanced technology, probably assumed to be better.

Dr. Bleiweiss is leading a pathology training program to train young pathologists who have just completed residency training in anatomic or anatomic/clinical pathology. In this year of fellowship, they will explore whether the range and frequency of benign diagnoses has changed with the advent of tomosynthesis, or if the use of tomosynthesis calls attention to nonspecific histology in greater numbers.  

They will compare the histology of benign core biopsies diagnosed during two 4-year periods: September 2007-August 2011, prior to the university’s switch to 3-D tomosynthesis, versus September 2011-August 2015, after the university transitioned to 3-D tomosynthesis for screening mammography.  

With the guidance and supervision of breast pathology specialists, the fellow will evaluate the microscopic characteristics of each case and compare the frequency of each diagnosis. They will also compare the subtypes and stages of malignancies diagnosed with each method. These results will provide evidence regarding which method is better overall or if one method is better for different subtypes or stages of breast cancer. 


Ira J. Bleiweiss, MD is a Professor of Pathology and Laboratory Medicine in the Perelman School of Medicine of the University of Pennsylvania.  He is director of the Breast Pathology Subspecialty Service at the Hospital of the University of Pennsylvania. Dr. Bleiweiss received his MD from St. Georges University School of Medicine, followed by residency in Anatomic and Clinical Pathology and fellowship in Surgical Pathology at The Mount Sinai Medical Center. After fellowship at Memorial Sloan Kettering Cancer Center, Dr. Bleiweiss returned to Mount Sinai, Department of Pathology to become Professor, Director of Surgical Pathology and Director of Anatomic Pathology. With more than 25 years of experience he oversees a completely subspecialized service dedicated to diagnosing breast lesions in specimens from hospital, as well as private practice outpatient settings.

Dr. Bleiweiss is well-known nationally and internationally for his expertise in breast pathology and is the author of more than 100 peer reviewed publications, largely related to breast cancer, many in the area of radiologic-pathologic correlation of image-guided breast core biopsies, a subject on which he co-authored a textbook.

His focus is distinctly multidisciplinary, and he is the current President of the International Society of Breast Pathology.

Grid Researcher Headshot - Bleiweiss

BCRF Investigator Since


Donor Recognition

The Women's Cancer Research Fund Award

Area(s) of Focus