Oesophageal and gastric cancer pathology reporting: a regional audit

AIM: To audit the information content of pathology reports of oesophageal and gastric cancer resection specimens in Wales. METHODS: All such reports from the 16 NHS histopathology laboratories in Wales in a one year period were evaluated for their information content. Two standards were used: (1) best practice reporting, and (2) a minimum dataset required for informed patient management that included clear statements on histological tumour type, depth of tumour invasion, lymph node involvement, and completeness of excision. RESULTS: 282 reports were audited. Minimum standards were achieved in 77% of gastric resections (156/203) and 53% of oesophageal resections (42/79). All laboratories achieved minimum standards in some gastric cancer reports (range 50-100%); three laboratories did not achieve minimum standards in any oesophageal cancer reports (range 0-100%). Best practice reporting was achieved in only 20% of gastric and 18% of oesophageal cancer reports. Failure to include an explicit statement on completeness of excision or involvement of the oesophageal circumferential resection margin were the most frequent causes of inadequate reporting. Most other data items were generally well reported, but apparent inadvertent omission of just one item was noted in many of the substandard reports. CONCLUSIONS: This audit shows the need to improve the information content of pathology reports in gastric and oesophageal cancer. The widespread implementation of template proforma reporting is proposed as the most effective way of achieving this. Multidisciplinary meetings of clinicians involved in cancer management should provide a forum for greater communication between pathologists and surgeons, and help to maintain standards of pathological practice.     

The use of a standard proforma in breast cancer reporting

AIM: To determine whether the introduction of a standard reporting proforma has led to an improvement in the completeness of histopathology reports for breast cancer excision specimens. METHODS: A standard reporting proforma was designed using the Royal College of Pathologists' minimum dataset for breast cancer histopathology reports and the national histopathology reporting form of the National Health Service (NHS) breast screening programme. This was introduced into our department in June 1999, with reports generated from the proforma replacing the standard text reports. The pathological information contained in 50 text reports issued before the introduction of the proforma and 50 reports generated using the proforma was compared with the minimum dataset and NHS breast screening programme guidelines. RESULTS: A general improvement in documentation of individual pathological features was noted after introduction of the proforma. This was most significant in relation to documentation of features, such as microcalcification and ductal carcinoma in situ. In addition, important features such as tumour grade, tumour size, and hormone receptor status were documented more frequently in the proforma group. There was an overall increase in the number of reports regarded as complete after introduction of the proforma. CONCLUSIONS: The introduction of a standard proforma led to a significant improvement in the completeness of breast cancer histopathology reports in this centre, but continued vigilance is needed to ensure that standards continue to improve.     

Histological precision of stereotactic core biopsy in diagnosis of malignant and premalignant breast lesions

The reliability of stereotactic core biopsy in the diagnosis of malignant and premalignant breast lesions was assessed in comparison to excision biopsy in patients with non-palpable suspicious breast lesions detected in a mammography breast screening programme. Fifty-two cases of malignancy and nine of atypical ductal hyperplasia were diagnosed on the programme during the two year period July 1993 to June 1995; two patients did not have excision biopsy. Stereotactic core biopsies and representative sections from 59 excision specimens from the same patients were assessed ‘blind’ by one pathologist. All 51 cancers diagnosed on stereotactic core biopsy were confirmed to be malignant on excision biopsy. There was 96% concordance between stereotactic core biopsy and excision biopsy for the diagnosis of invasive or in situ cancer, and 78% concordance for the type of cancer. The stereotactic core biopsy and excision biopsy diagnoses were: invasive ductal carcinomas (39 on stereotactic core biopsy vs. 33 on excision biopsy), mucinous carcinomas (1 vs. 2), invasive lobular carcinomas (3 vs. 8), and in situ carcinomas (8 vs. 8), two of which had invasive cancer present only in the stereotactic core biopsy. Of the nine cases of atypical ductal hyperplasia diagnosed on stereotactic core biopsy, eight had an excision biopsy, six showed low nuclear grade in situ or invasive cancer, one had a 3mm focus of high grade invasive ductal cancer and one was atypical ductal hyperplasia. In the invasive ductal carcinoma group stereotactic core biopsy underestimated tumour grade: in nine cases (31%) the cancer at excision was of a higher grade. Stereotactic core biopsy is a reliable alternative to excision biopsy in the diagnosis of breast cancer, however, stereotactic core biopsy may underestimate tumour grade in invasive ductal carcinoma and may not differentiate between invasive ductal carcinoma and lobular carcinoma. It is recommended that the diagnosis of atypical ductal hyperplasia on stereotactic core biopsy be followed by excision biopsy, as stereotactic core biopsy underestimates the presence of cancer in this group.     

Quality control in immunocytochemistry: experiences with the oestrogen receptor assay.

AIMS: To evaluate the feasibility of an interlaboratory quality control programme in immunohistochemistry. METHODS: Several pathology laboratories were asked to carry out immunohistochemical oestrogen receptor staining on a set of freeze dried cryostat sections of breast cancer tissue. The sections and protocols for staining and semi-quantitative scoring were mailed to the participating laboratories in two trials. The oestrogen receptor content of the breast cancer samples was determined by radioligand binding assay on the tumour cytosol. RESULTS: In the first trial 11 laboratories (response rate 60%) participated. Eight (73%) of the participants scored within a 95% confidence interval and all but one correctly classified the tumour as receptor positive. In the second trial all 20 participating laboratories (response rate 55%) correctly scored one tumour sample as negative and 18 of them (90% of respondents) correctly classified the two other tumour samples as receptor positive. In a quantitative evaluation a histochemical score within 95% confidence interval limits was provided by eight (40%) and 12 (60%) of the participants. CONCLUSIONS: Semiquantitative scoring of immunocytochemical staining is valuable for performing correlative inter-laboratory studies, although this scoring protocol may not be required for diagnosis or prognosis. Significant inter-laboratory variability exists, leading to qualitatively correct receptor classification in 100% of receptor negative and 80% of receptor positive cases, and quantitative agreement in only about half of the cases. The perceived variability is not caused by systematic differences in the choice of the immunocytochemical technique, or the mailing of freeze dried sections. Quality control programmes should be included in the standard procedures of each diagnostic immunohistochemistry laboratory.     

Reporting basal cell carcinoma: a survey of the attitudes of histopathologists

AIMS: To investigate the histopathological reporting of basal cell carcinoma. METHODS: Methods of classification and attitudes to excision margins were ascertained from histopathologists in 130 centres; 82 replies were obtained (63% response rate). RESULTS: 24% of those replying did not use any classification system for basal cell carcinoma. The remainder (76%) used a wide variety of different classification systems. A small number (9%) of those questioned felt reporting on completeness of excision was not important. The majority of histopathologists considered the excision margin was worth reporting but there were differences in methods of processing and reporting biopsies. CONCLUSIONS: There is considerable variation in histopathological reporting of basal cell carcinoma. There is a need for uniformity of histopathological reporting to allow both improved management decisions and comparative audit of this extremely common skin cancer.     

The clinical and pathological differences in prevalent round screen-detected and symptomatic invasive breast cancer

The potential benefits of breast cancer screening include the detection of cancers at a more favourable stage, however, cancers detected during the prevalent round of screening may differ from true screen-detected cancers. These differences are poorly defined. This study prospectively assessed all women between 50 and 64 years of age undergoing curative surgery for breast cancer, both screen-detected and symptomatic, in one screening centre during the prevalent round of the national breast cancer-screening programme. Four hundred and thirty seven patients (364 screen-detected and 73 symptomatic patients) underwent surgery for breast cancer. Symptomatic breast cancers were of a higher grade (p < 0.0001; Chi2) and less likely to be oestrogen receptor positive (49% versus 88%; p < 0.0001; Fisher's exact test); however there was no difference in size of tumour or axillary nodal positivity. This study suggests that tumours detected by screening during the prevalent round of a screening programme are of a more prognostically favourable type than symptomatic breast cancers in the same age group.     

Classification of R1 resections for pancreatic cancer: the prognostic relevance of tumour involvement within 1 mm of a resection margin

Aims:  The current Royal College of Pathologists guidelines for pancreatoduodenectomy specimen reporting recommend that microscopic evidence of tumour within 1 mm of a resection margin (RM) should be classified as R1. No clinical evidence exists to justify this classification. The aim of this study was to identify the proportion of pancreatoduodenectomy specimens in which 'equivocal' RMs are present (tumour involvement within 1 mm of, but not directly reaching, one or more resection margins) and whether the survival of these patients was similar to that of patients with 'unequivocal' RM involvement.
Methods and results:  Patients with histologically confirmed pancreatic ductal adenocarcinoma undergoing pancreatoduodenectomy between 1997 and 2007 ( n  = 163) were identified from a prospective database. One hundred and twenty-eight cases (79%) were classified as R1. Of these, 57 (45% of all R1 cases) were based on 'equivocal' margin involvement. There was no significant difference in overall survival between equivocal and unequivocal R1 resections (log rank, P  = 0.102). All R1 resections had a poorer survival on univariate (log rank, P  = 0.013), but not multivariate, analysis (Cox, P  = 0.132).
Conclusions:  Our results indicate that cases with microscopic tumour involvement within 1 mm of a resection margin should be considered synonymous with incomplete excision for resected pancreatic cancer.     

Reducing indications for radial scar surgical excision in Slovenian breast cancer screening program

PurposeManagement of the radial scar (RS)/complex sclerosing lesion (CSL) diagnosed by core needle biopsy (CNB) in breast cancer screening population (BCSP) is controversial due to its intrinsic malignant potential. We aimed to determine (i) the rate of upgrade of the RS/CSL to malignant lesions and (ii) radiological characteristics and CNB histopathological findings of the lesions related to the upgrade of the RS/CSL to malignant lesions after surgical excision in our BCSP.Patients and methodsDatabase of Slovenian National Breast Cancer Screening Program was checked for terms RS/CSL in all patients who underwent CNB in the period 2008–2018. The ratios of upgrade from CNB RS/SCL to malignant lesions after surgical excision were calculated with specific interest to the radiological characteristics and the CNB patohistologically findings of the lesions.ResultsOf 162 patients with diagnosis of RS/CSL on the CNB, 121/156 (78%) cases underwent surgical excision. 6 of 121 (5%) cases were upgraded to a malignant diagnosis in surgical specimen, 3 cases of invasive carcinoma and 3 cases of DCIS, respectively. Five of the upgraded cases (5/6, 83.3%) showed atypical epithelial proliferative lesions (AEPL) on CNB. In one upgraded case without AEPL the lesion presented as 33 mm architectural distortion with microcalcifications on the mammogram.ConclusionsIn BCSP setting RS/CSL without AEPL/papilloma and those measuring less than 2 cm in the largest diameter can be followed radiologically. Increasing the number of cores and adequate sampling of the periphery and the centre of the RS/CSL improves the pick-up rate of associated atypia/malignancy.     

Colorectal cancer pathology reporting: a regional audit.

AIMS: To audit the information content of pathology reports of colorectal cancer specimens in one National Health Service region. METHODS: All reports of colorectal cancer resection specimens from the 17 NHS histopathology laboratories in Wales during 1993 were evaluated against: (a) standards previously agreed as desirable by pathologists in Wales; and (b) standards considered to be the minimum required for informed patient management. RESULTS: 1242 reports were audited. There was notable variation in the performance of different laboratories and in the completeness of reporting of individual items of information. While many items were generally well reported, only 51.5% (640/ 1242) of rectal cancer reports contained a statement on the completeness of excision at the circumferential resection margin and only 30% (373/1242) of all reports stated the number of involved lymph nodes. All of the previously agreed items were contained in only 11.3% (140/1242) of reports on colonic tumours and 4.0% (40/1242) of reports on rectal tumours. Seventy eight per cent (969/1242) of colonic carcinoma reports and 46.6% (579/ 1242) of rectal carcinoma reports met the minimum standards. CONCLUSIONS: The informational content of many routine pathology reports on colorectal cancer resection specimens is inadequate for quality patient management, for ensuring a clinically effective cancer service through audit, and for cancer registration. Template proforma reporting using nationally agreed standards is recommended as a remedy for this, along with improved education, review of laboratory practices in the light of current knowledge, and further motivation of pathologists through their involvement in multidisciplinary cancer management teams.     

Accuracy of frozen section diagnoses of breast lesions after introduction of a national programme in mammographic screening

AIMS: By introducing mammography screening programmes, the size of the detected breast lesions became smaller and the histopathological interpretation problems greater. The study's aim was to analyse the risks and possible limitations of the frozen section method. METHODS AND RESULTS: Frozen section consultations of breast lesions (n=559) 2 years before and 6 years after launching a national mammographic screening programme in 1992 were evaluated in regard of the benign/malignant ratio, tumour size, preoperative frozen section results and final permanent section diagnoses. The breast frozen section examinations of 1990 compared with those from 1998 declined from 70.7% (299/423) to 62.2% (260/418) (P < 0.01), the benign/malignant ratio from 1.09 to 0.54 (P < 0.0001), the rate of the conclusive, correct frozen section diagnoses from 96.3% to 91.9% (P < 0.03). The sensitivity dropped from 92.3% to 87.6%, the negative predictive value from 95.7% to 88.3%, whereas the negative likelihood ratio rose from 0.08 to 0.12. The 'small' (< or = 10 mm) invasive breast carcinomas increased from 14.2% to 22.3% (P < 0.01) and the 'in situ' carcinomas from 2.1% to 6.6% (P < 0.05). CONCLUSIONS: The declining sizes of breast tumours (< or = 10 mm), especially from radiologically detected lesions and sometimes without a macroscopic correlate, create new limitations and changing indications in the histopathological interpretation. Considering the performance of new diagnostic methods (i.e. large core needle biopsies), frozen sections of surgical specimens should not be the primary diagnostic procedure for breast lesions and should be performed only after other preoperative methods have failed.     

Comparative study of the histopathology of breast cancer in a screened and unscreened population investigated by mammography

The histopathology of 360 surgical resections for breast cancer in a consecutive series of patients aged 45-69 years from 1979-1983 is described. Two hundred and seventeen patients who were offered screening (screened patients) were compared with 143 patients who were referred as out-patients with breast problems and were not offered screening (unscreened patients). Both groups were investigated by mammography. Comparisons between tumour staging, grading and quadrant involvement are reported. In the screened patients 31% were in the in-situ stage or had an invasive carcinoma less than 1.0 cm in maximum diameter, compared with 7% in the unscreened patients. Conversely 26% of the screened patients had cancers greater than 2.0 cm compared with 52% in the unscreened group. The percentage of cancer patients with lymph node metastases was comparable in both 1.0-2.0 cm and greater than 2.0 cm groups of invasive carcinoma. There were more multiquadrant cancers in the unscreened patients (32%) than screened patients (17%) and this was mainly due to differences in the incidence of carcinomas 1.0-2.0 cm in diameter. This suggests that invasive tumours of comparable size are more likely to produce symptoms leading to detection if multiquadrant. Multicentric cancers were more common in unscreened patients. Differences in the histological grading related to tumour size were found within the screened and unscreened groups but not between the two groups.     

Intraoperative imprint cytology of sentinel lymph nodes in breast cancer: initial experience and lessons learnt in establishing a new practice

AIMS: The initial 18 months experience of performing intraoperative imprint cytology for patients with breast cancer undergoing sentinel lymph node biopsy is described for a single institution. The learning process is compared with published results from institutions with many years of experience in order to assess progress in reaching those ideal results, and the methodology used by these institutions is reviewed. METHODS: A retrospective review was undertaken of the intraoperative imprint cytology results from 103 patients with breast cancer (yielding a total of 170 lymph nodes) who underwent imprint cytology of their sentinel lymph node. The intraoperative imprint cytology results were compared with the final histopathological results. Details regarding the primary tumour characteristics and metastatic deposit size were recorded. RESULTS: The sensitivity for imprint cytology was 31.1%, with a specificity of 100% and overall accuracy of 77.8%. The sensitivity for detecting macrometastases (>2 mm diameter) was 61.9% and the sensitivity for micrometastases (<2 mm diameter) and including isolated tumour cells was 4.2%. CONCLUSIONS: The differences in sensitivity in comparison with many studies in the literature are multifactorial, and include technical aspects, such as the methodology used in the final histopathological and intraoperative evaluation of the sentinel lymph nodes, interpretative difficulties, and much lower case numbers. Furthermore, these numbers represent early experience and methods to improve sensitivity and overall accuracy are detailed in this paper.     

Breast cancer screening pathology: an assessment of the practise and needs in Belgium and Luxembourg

Education and quality assurance (QA) in breast screening pathology have been encouraged by the Europe Against Cancer programme. As a prerequisite for the set-up of a QA programme in Belgium and in the Grand Duchy of Luxembourg, an inquiry was initiated to evaluate the daily practise in breast pathology, the modalities in handling and analysing breast specimens and the willingness of the pathologists to participate in a QA scheme. Of the 278 mailed questionnaires, 109 confidential and valid questionnaires were returned, meaning a participation rate of 40%. All 109 respondents indicated their willingness to voluntarily participate in the further QA programme. Segmental resections for conservative surgery and excision biopsies ranked first and second, respectively, in examination requests. Of the respondents, 50% complained about the lack of clinical information on the pathology request form. A multidisciplinary team approach for the diagnosis of screen-detected lesions was deemed desirable by 87% of the respondents, but only 16% of them actually participate in such pre-operative meetings. Even more puzzling is that 75% of the respondents report regular unavailability of the control radiogram of the surgical specimen removed for non-palpable lesions. One-quarter to one-third of the pathologists still regularly perform frozen sections on microcalcifications or tumours smaller than 1 cm. However, 81% of the respondents estimate that pre-operative diagnosis is not appropriate for this type of lesion. The results of this inquiry show that the guidelines for the diagnosis of screen-detected breast lesions are not yet fully applied in daily practise. The development of local comprehensive breast teams involving a pathologist should improve the co-ordination between the medical disciplines, represent an important way of disseminating the guidelines on breast screening pathology and stimulate the relay unit to conduct QA programmes. Received: 31 March 2000 / Accepted: 9 May 2000     

The continued value of central histopathological review of testicular tumours

AIMS: Central histopathological review of testicular tumours prior to definitive treatment can have an important impact on patient management. This study was designed to assess the continued value of central review in the light of increasing subspecialization and increased numbers of consultant histopathologists. MATERIALS AND RESULTS: The original and review reports of 291 testicular cancer specimens from 1998 to 2002 were analysed, looking particularly at major diagnosis, vascular invasion and the tumour elements within non-seminomatous germ cell tumours (NSGCT). When a diagnosis was altered any effect on subsequent patient management was assessed. There was a discrepancy in tumour type in 11 cases (4%) compared with 6% in 1992-1997. The commonest change was from seminoma to NSGCT or combined germ cell tumour (5/11). There was also diagnostic difficulty with spermatocytic seminoma (3/11). The clinical management of all 11 cases was influenced as a result of the review diagnosis. Discrepancies in vascular invasion were noted in 13 of the 126 NSGCTs (10%) compared with 20% in 1992-1997. Differences in NSGCT tumour elements, though clinically less important, were frequent in both groups. CONCLUSIONS: There continues to be a small number of significant and clinically important errors identified following central histopathological review of testicular tumours. This study highlights the value of central review and supports its continued practice in the management of testicular tumours.     

Non-neoplastic granulosa cells within ovarian vascular channels: a rare potential diagnostic pitfall

AIMS: To describe six cases seen in consultation in which artefactual vascular involvement within the ovary by benign granulosa cells caused diagnostic confusion. METHODS/RESULTS: In five cases, the initial favoured diagnoses of the submitting pathologists were metastatic carcinoma (three cases) and immature neural elements within a teratoma (two cases). In two cases, the ovary contained a benign cystic teratoma (one with struma ovarii), in two cases endometriosis, in one case follicular cysts, and in the other no pathological lesion was present. In all cases, several small ovarian vascular channels contained cohesive groups of cells with mildly atypical nuclei and cytoplasm, which varied from scant to abundant and eosinophilic. In four cases, mitotic figures were identified. The cells were morphologically consistent with benign granulosa cells and were associated in four cases with a nearby follicle lined by similar cells. There was no evidence of a mass lesion, grossly or histologically, to suggest a granulosa cell tumour. The nature of the cells was confirmed using immunohistochemistry for alpha inhibin and calretinin in one case. CONCLUSIONS: This phenomenon is probably an artefact secondary to surgical trauma or sectioning within the laboratory; alternatively, it could be related to ovulation. It is important that this benign process is not misinterpreted as cancer, either primary or metastatic, which may prompt inappropriate treatment or investigations that are not needed.     

Histopathological features of breast cancer in carriers of ATM gene variants

AIMS: Germline variants in the ataxia telangiectasia mutated (ATM) gene have been implicated in increased breast cancer risk. The aim of this study was to determine whether the histopathology of breast cancers occurring in ATM variant carriers is distinctive or resembles the described BRCA1 mutation-associated phenotype. METHODS: The histopathological features of breast cancers occurring in ATM variant carriers from multiple-case breast cancer families were compared with matched controls. The test group included 21 cases of in situ and/or invasive cancer from carriers of either the IVS10-6T-->G, 2424V-->G or 1420L-->F ATM variants in the absence of BRCA1 or BRCA2 mutations. An additional four invasive cancers from carriers of a pathogenic BRCA1 mutation in the context of a familial ATM variant were also examined. RESULTS: The histopathology of breast cancers in ATM variant-only carriers was not significantly different from controls and known features of BRCA1 mutation-associated cancer were rarely seen. In contrast, these features were prominent in the small group of cases with a pathogenic BRCA1 mutation. CONCLUSIONS: Breast cancer occurring in carriers of ATM variants is not associated with distinctive histopathological features and does not resemble the tumour phenotype commonly observed in BRCA1 mutation carriers.     

The value of cytokeratin immunohistochemistry in the evaluation of axillary sentinel lymph nodes in patients with lobular breast carcinoma

BACKGROUND: Cytokeratin immunohistochemistry (IHC) reveals a higher rate of occult lymph node metastases among lobular carcinomas than among ductal breast cancers. IHC is widely used but is seldom recommended for the evaluation of sentinel lymph nodes in breast cancer patients. Objective: To assess the value of cytokeratin IHC for the detection of metastases in sentinel lymph nodes of patients with invasive lobular carcinoma. METHODS: The value of IHC, the types of metastasis found by this method, and the involvement of non-sentinel lymph nodes were analysed in a multi-institutional cohort of 449 patients with lobular breast carcinoma, staged by sentinel lymph node biopsy and routine assessment of the sentinel lymph nodes by IHC when multilevel haematoxylin and eosin staining revealed no metastasis. RESULTS: 189 patients (42%) had some type of sentinel node involvement, the frequency of this increasing with increasing tumour size. IHC was needed for identification of 65 of these cases: 17 of 19 isolated tumour cells, 40 of 64 micrometastases, and 8 of 106 larger metastases were detected by this means. Non-sentinel-node involvement was noted in 66 of 161 cases undergoing axillary dissection. Although isolated tumour cells were not associated with further lymph node involvement, sentinel node positivity detected by IHC was associated with further nodal metastases in 12 of 50 cases (0.24), a proportion that is higher than previously reported for breast cancer in general. CONCLUSIONS: IHC is recommended for the evaluation of sentinel nodes from patients with lobular breast carcinoma, as the micrometastases or larger metastases demonstrated by this method are often associated with a further metastatic nodal load.     

乳腺微小病灶立体定位切除活检的临床应用

目的：探讨乳腺微小病灶经B超、钼靶定位切除活检的临床应用价值。方法：分别对55例、40例临床触诊阴性的乳腺微小病灶进行B超、钼靶定位切除活检。结果：发现乳腺纤维腺瘤35例（36.84%）,乳腺增生29例（30.53%）,乳管内乳头状瘤7例（7.37%）,慢性乳腺炎5例（5.26%）,轻度不典型增生4例,中度不典型增生2例,乳腺癌19例（20.00%）,其中0期乳腺癌4例,I期乳腺癌5例,II乳腺癌10例。结论：利用B超及钼靶X线引导下金属导丝定位切除乳腺微小病灶病检具有重要的临床应用价值。     

Diagnostic accuracy of stereotactic core biopsy in a mammographic breast cancer screening programme

Stereotactic core biopsy was performed on 200 women for 206 mammographically suspicious non-palpable lesions detected over a period of 2 years as part of the Australian national programme for early detection of breast cancer. This study aimed to assess the reliability of stereotactic core biopsy in this context and to develop a protocol for the evaluation of stereotactic core biopsy in mammographically detected non-palpable breast lesions. Fifty-one of 52 malignant lesions found by stereotactic core biopsy were confirmed by excision biopsy (one woman declined excision). Nine (4.5%) women had atypical ductal hyperplasia on stereotactic core biopsy; at excision, six were low grade carcinomas (in situ or invasive carcinomas), one was a 3 mm focus of grade 3 invasive duct carcinoma, one was atypical ductal hyperplasia, and one patient refused excision biopsy. In 29 (14.5%) women the histology of the stereotactic core biopsy was considered not to correlate with the radiological abnormality, and excision biopsy was advised: in four of these women carcinomas were found. One hundred and ten (55%) women had 116 benign lesions on stereotactic core biopsy: on follow-up, one of these patients has been found to have a carcinoma. Core biopsy number and sequence were analysed demonstrating that no particular biopsy was more diagnostic than any other, and that the diagnostic yield of three cores was statistically equal to that of five cores. The procedure was well-tolerated and there were few complications. Thus, stereotactic core biopsy is an accurate and safe method for diagnosis of mammographically detected non-palpable breast lesions, and we believe it is the diagnostic technique of choice in breast cancer screening programmes. However, a stereotactic core biopsy diagnosis of atypical ductal hyperplasia requires excision biopsy since a diagnosis of low grade intraduct carcinoma cannot be excluded. Furthermore, if tissue obtained by stereotactic core biopsy does not correlate with the mammographic abnormality, excision biopsy should be performed.