Mrs S’s GP referred her to Dr M, specialist breast surgeon, as she had noticed a lump in one of her breasts. Dr M arranged mammography and fine-needle aspiration cytology (FNAC) of the lesion, which were carried out on the same day. Dr M’s initial clinical opinion was that the lump was benign.
Mrs S’s mammogram was negative; the FNAC report stated that there were many benign ductal cells but a few clusters of malignant cells. At a clinical pathology case conference (CPC), Dr M discussed the FNAC results with the reporting pathologist, Dr V.
They had seen two patients recently who had normal mammography and malignant cells in the FNAC; these turned out to be cases of breast carcinoma, and they thought that Mrs S’s case might be similar.
Dr V remembers discussing the possibility of carrying out frozen section histology to establish the diagnosis, and thus the optimal surgical plan. Dr M has a different recollection and remembers Dr V saying that this was not needed, given the findings of the FNAC.
Dr M re-examined Mrs S. He now felt that the lesion had characteristics of a malignant tumour and advised Mrs S to have wide excision of the lump with an axillary lymph-node clearance.
Histology of the excised tissue revealed no evidence of tumour. Dr V reviewed the FNAC slides and agreed there was no definite evidence of malignancy.
Mrs S sued Dr V for misinterpreting the FNAC result and performing what she alleged were an unnecessarily large surgical excision and spurious axillary clearance.
We took advice from an expert in cytopathology and histopathology.
The expert noted that although there were some signs of cellular atypia in the FNAC slides, there were no changes to signify a definite diagnosis of malignancy.
The expert discussed the means by which the evidence from all three avenues (clinical examination, mammography and FNAC) needed to be considered together, in context, to decide on an appropriate plan. This approach minimised danger to patients by considering all the results together, to prevent under- or over-treatment.
The expert pointed out that FNAC requires a very high degree of skill and experience to interpret.This is why pathologists review each other’s slides in borderline cases.
Even so, it is still possible for false positive and false negative results to occur. The expert felt that, where there is disagreement between the diagnostic modalities, the wisest course of action is lumpectomy and intraoperative histological examination by frozen section to confirm the diagnosis. Where the diagnostic modalities conflict, a cautious and considered approach is needed. We settled the case, with liability being shared equally between Drs M and V.
CPCs are a good way for clinicians and pathologists to ensure that they are using information from investigations optimally. However, as this case demonstrates, it is essential to keep records of the discussions and the agreed plan.
This allows the decision-making process to be understood in its full context and clarifies everyone’s position, should a claim or complaint ensue.
FNAC as part of the triple assessment
- may be superseded by core biopsy of breast lesions.
- magnetic resonance imaging of the breast may become an increasingly useful tool, helping to make these difficult decisions easier in future.
- Eltahir A et al. ‘The Accuracy of “One-Stop” Diagnosis for 1110 Patients Presenting to a Symptomatic Breast Clinic’, J R Coll Surg Edinb, 44:226–30 (1999).
- Chuo CB and Corder AP. ‘Core Biopsy versus Fine Needle Aspiration Cytology in a Symptomatic Breast Clinic’, Eur J Surg Oncol. 29(4):374–8 (2003).
- Kneeshaw PJ et al. ‘Current Applications and Future Direction of MR Mammography’. Br J Cancer, 88(1):4–10 (2003).