Columnar cell lesions: a consensus study among pathology trainees.

Columnar cell lesions of the breast are a spectrum of lesions in the terminal duct lobular units, which include columnar cell change, columnar cell hyperplasia, and columnar cell change or columnar cell hyperplasia with atypia. The latter was designated by the World Health Organization as flat epithelial atypia. We studied a group of pathology trainees (pathology residents and fellows) as a model for the impact of a training tutorial on the ability to distinguish various types of columnar cell lesions. Twenty-four test cases of columnar cell lesions, including 8 cases each of columnar cell change, columnar cell hyperplasia, and flat epithelial atypia, were prepared after an independent consensus on diagnosis by 2 senior pathologists with expertise in breast pathology. Fourteen pathology trainees were given a slide tutorial for the diagnostic criteria of columnar cell lesions at a multiheaded microscope. All 14 trainees entered their diagnoses of columnar cell lesions independently before and after the tutorial. The kappa values of columnar cell lesions, columnar cell hyperplasia, and flat epithelial atypia among 14 pathology trainees were 0.42, 0.25, and 0.39 before the tutorial and 0.56, 0.41, and 0.60 after the tutorial, respectively. The agreements on columnar cell lesions, columnar cell hyperplasia, and flat epithelial atypia after the tutorial were significantly better than those before the tutorial. No significant difference in agreement was observed on columnar cell change before and after the tutorial, but the kappa value improved. We conclude that appropriate tutorial training of diagnostic criteria can increase diagnostic agreement on columnar cell lesions among pathology residents, fellows, and presumably general pathologists in practice.