Phyllodes tumor of the breast. A cytomorphologic approach based on evaluation of epithelial cluster architecture.
OBJECTIVE
To develop more useful criteria for differentiating benign phyllodes tumor (BPT) from fibroadenoma (FA) of the breast on fine needle aspiration cytology (FNAC), with a focus on architectural features of epithelial clusters.


METHODS
The smears of 18 cases obtained by preoperative FNAC, each with tissue-proven BPT, were compared to those of 25 cases of FA. Several features of epithelial clusters in both groups were studied, with histologic correlation.


RESULTS
BPT exhibited large epithelial clusters longer than 1 mm, with a wavy or folded shape, that could be distinguished from the small or medium-sized clusters with tubular, blunt-branching or monolayered contours in FA. This appearance of BPT was equivalent to the characteristic phyllodes pattern of its histology.


CONCLUSIONS
The size and shape of epithelial clusters are important diagnostic clues in addition to several findings that have been described as differentiating BPT from FA on FNAC.
Shimizu
Ken
K
Department of Anatomic and Diagnostic Pathology, Dokkyo University School of Medicine, 880, Mibu, Tochigi, 321-0293, Japan.
Korematsu
Motoko
M
D000293:Adolescent; D000328:Adult; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology*; D003937:Diagnosis, Differential; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D018226:Fibroadenoma / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D003557:Phyllodes Tumor / Q000175:diagnosis / Q000473:pathology*