The sensitivity of needle core biopsy in combination with other investigations for the diagnosis of phyllodes tumours of the breast.

BACKGROUND: The sensitivity of needle-core biopsy (NCB) in diagnosing phyllodes tumours has only been addressed by a handful of small studies. The aim of this study was to analyse the sensitivity of NCB in the diagnosis of phyllodes tumours and to compare this to the sensitivity of other commonly performed investigations. A secondary aim was to assess the effect of various patient and disease factors on the rate of false negative test results.

METHODS: Pathology databases were interrogated to identify all patients with the SNOMED term M-9020 or the word phyllodes in specimen reports. Excisional specimen reports were matched to prior FNAC reports, NCB reports and imaging reports.

RESULTS: Ninety-one patients had a confirmed phyllodes tumour on excision. The sensitivity of FNAC, NCB and imaging for diagnosing phyllodes tumours was 40%, 63% and 65% respectively. The sensitivity of imaging and NCB was greater for borderline and malignant lesions. Combining cytohistological and radiological tests improved sensitivity to 76%. A younger age was associated with a greater false negative rate for all tests. Borderline and malignant phyllodes tumours were significantly associated with advancing age and greater lesion size on imaging and histology.

CONCLUSIONS: This is the largest report to date assessing the sensitivity of NCB in the diagnosis of phyllodes tumours. Increased sensitivity in the diagnosis of phyllodes tumours can be achieved by combining cytohistological and radiological test results. The novel association between younger age and false negative results warrants further investigation. The most likely explanation is a reluctance to diagnose phyllodes tumours in young women given the increased prevalence of cellular fibroadenomas in this age group.