Fine needle aspiration cytology of mammary hamartoma: a review of nine cases with histological correlation.

Mammary hamartoma is a breast lesion rarely reported by fine-needle aspiration cytology (FNAC). We report on our experience of FNAC in nine cases confirmed by biopsy. We searched hospital case files for mammary hamartoma or similar lesions (fibrolipomas, lipomas, fibromas, etc.), and cases included were only those in which both FNAC and a histopathological study had been performed. The cytological features that were analysed included epithelial components, mesenchymal fragments and isolated cells dispersed in the background. The patients ranged in age from 25 to 58 years (mean 40 years), and the lesions were predominantly in the right breast and upper outer quadrant. The duration varied from 1 to 20 years. Mammographic features were characteristic revealing well-circumscribed masses of heterogeneous radiodensity and by ultrasonography were hypoechoic without calcification. Grossly, these lesions were oval to round, well-demarcated masses, ranging in diameter from 10 to 80 mm. The tumours were firm, rubbery and white, consisting largely of dense fibroconnective tissue with variable amounts of adipose tissue and glandular elements. Cytological samples showed two components, epithelial and mesenchymal. The cellularity was variable and was composed of lobular cells forming acini, ductal cells, occasional apocrine and foamy cells; myoepithelial cells and isolated naked nuclei were also observed. Adipose tissue and dense fibrous tissue were observed, occasionally with epithelial cells attached, and this finding was an important feature for diagnosis. We considered that the cytological findings could help to diagnose mammary hamartoma, FNAC making a rapid and very important technique for the diagnosis of this pathology.