Cytomorphologic and morphometric limitations of the assessment of atypia in fibroadenoma of the breast.

OBJECTIVE: To investigate the relevance of nuclear morphometry in separating the categories of "fibroadenoma" and "fibroadenoma with atypia." STUDY DESIGN: Thirty consecutive breast lumps, on which a fine needle aspiration (FNA) diagnosis of fibroadenoma was followed by excision and histopathologic confirmation of the diagnosis, were included. Atypia on cytology was based on cell overlap, nuclear enlargement and cell dyscohesion. Nuclear morphometric comparison was carried out between the categories of fibroadenoma, fibroadenoma with atypia and grade 1 ductal carcinoma cases that formed part of an earlier study. The parameters employed were area, roundness, diameter, perimeter and grey level. RESULTS: Among the 30 cases of fibroadenoma reported on FNA, an additional component of atypia was noted in 5. On subsequent histopathology, atypia was not confirmed in any of the cases. On morphometric analysis, a significant difference was noted between fibroadenoma and fibroadenoma with atypia categories, as between fibroadenoma and grade 1 ductal carcinoma cases. However, no significant difference was noted between fibroadenoma with atypia and grade 1 ductal carcinoma cases. CONCLUSION: FNA assessment of atypia in cases of fibroadenoma is difficult. Even conventional nuclear morphometry, though supporting the initial impression of atypia, does not help with this assessment. Also, based on morphometry alone, there may be difficulty separating fibroadenomas with atypia and grade 1 ductal carcinomas. Larger studies, employing other morphometric parameters, such as chromatin texture and fractal dimension, may shed further light on the subject.