Differences in immunohistochemistry utilization by general and breast subspecialty pathologists at a large academic institution

Objectives: Immunohistochemistry (IHC) can be a useful adjunct in diagnostic breast pathology, but best practices have not been clearly established. We sought to compare the patterns of p63 utilization between general pathologists (GP) and subspecialized breast pathologists (BP), analyze diagnostic discrepancy rates, and identify types of lesions requiring immunohistochemistry.

Methods: The pathology database was searched over 6-year period to identify breast needle core biopsy cases utilizing p63 and subsequent excision results.

Results: P63 was ordered more frequently by BP (2.3% of cores) compared to GP (1.1% of cores, p = 0.0005). The most frequent utilization of p63 by GP for benign lesions (44.0%) followed by invasive carcinomas (36.0%) while BP most frequently ordered p63 on invasive carcinomas (49.5%) and DCIS (26.6%).

Conclusions: While IHC use may be thought to be most helpful to those with less experience or knowledge in breast pathology, these results suggest that utilization is increased with subspecialty training.