[251] Differences in Tumor Grade of Invasive Breast Carcinomas in Core Biopsy and Excision: An Analysis of 142 Cases

Chiraag D Patel, Dimple M Pandya, Jingxuan Liu, Cliff Bernstein, Carmen Tornos. Stony Brook University Medical Center, Stony Brook, NY

Background: Nottingham histologic score (NHS) is widely used to determine the tumor grade of invasive breast cancers. Some studies done in other tissues support the idea of mitosis being dependent of ischemia time. The aim of this study was to compare the tumor grade in the core biopsy (ischemia time less than 10 minutes), and surgical excision (ischemia time greater than 1 hour).
Design: 142 cases of invasive breast cancer that had core biopsies and surgical resections done at out institution were retrieved from our files. The same pathologist reviewed all 142 cases, and determined the NHS examining 50 high power fields in each case using the same microscope. Architectural score, nuclear grade and mitotic count were compared in all cases.
Results: 119 cases (83.80%) had a similar NHS in the core and excision. 20 cases (14.08%) had a higher NHS in the excision, and 3 (2.12%) in the core. A higher grade in the excision was due to higher mitotic count in 16 cases, higher nuclear grade in one case, and more than one parameter in 3 cases. Despite the fact that all core biopsies had an ischemia time of 10 minutes or less, they all had poor nuclear detail with homogeneous chromatin pattern, and pyknotic – like nuclei. This was seen in all cases regardless of the radiological method used (stereotactic, ultrasound or MRI guided). This affected not only nuclear grading but also mitotic count (mitoses were difficult to separate from pyknotic nuclei). The nuclear detail was better in most excision specimens despite a longer ischemia time.
Conclusions: NHS in core biopsy and excision is concordant in 83.8% of the cases. 14.08% of cases have a higher score in the excision due to better preservation of nuclear detail. Despite a longer ischemia time, practically all excisions had surprisingly better nuclear detail, allowing easier mitotic counts and nuclear grading. The reason for the poor nuclear detail in all cores is uncertain, but could be related to the technique used by the radiologists to retrieve the tissue. This finding deserves further investigation.
Category: Breast

Monday, March 4, 2013 1:00 PM

Poster Session II # 35, Monday Afternoon

 

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