Fine needle aspiration of the breast. A probabilistic approach to diagnosis of carcinoma

Real-World Diagnostic Accuracy of the On-Site Cytopathology Advance Report (OSCAR) Procedure Performed in a Multidisciplinary One-Stop Breast Clinic

Fine-needle aspiration (FNA) cytology has been widely used for the diagnosis of breast cancer lesions with the objective of differentiating benign from malignant masses. However, the occurrence of unsatisfactory samples and false-negative rates remains a matter of concern. Major improvements have been made thanks to the implementation of rapid on-site evaluation (ROSE) in multidisciplinary and integrated medical settings such as one-stop clinics (OSCs). In these settings, clinical and radiological examinations are combined with a morphological study performed by interventional pathologists. The aim of our study was to assess the diagnostic accuracy of the on-site cytopathology advance report (OSCAR) procedure on breast FNA cytologic samples in our breast OSC during the first three years (April 2004 till March 2007) of its implementation. To this goal, we retrospectively analyzed a series of 1820 breast masses (1740 patients) radiologically classified according to the American College of Radiology (ACR) BI-RADS lexicon (67.6% being either BI-RADS 4 or 5), sampled by FNA and immediately diagnosed by cytomorphology. The clinicoradiological, cytomorphological, and histological characteristics of all consecutive patients were retrieved from the hospital computerized medical records prospectively registered in the central information system. Histopathological analysis and ultrasound (US) follow-up (FU) were the reference diagnostic tests of the study design. In brief, we carried out either a histopathological verification or an 18-month US evaluation when a benign cytology was concordant with the components of the triple test. Overall, histology was available for 1138 masses, whereas 491 masses were analyzed at the 18-month US-FU. FNA specimens were morphologically nondiagnostic in 3.1%, false negatives were observed in 1.5%, and there was only one false positive (0.06%). The breast cancer prevalence was 62%. Diagnostic accuracy measures of the OSCAR procedure with their 95% confidence intervals (95% CI) were the following: sensitivity (Se) = 97.4% (96.19-98.31); specificity (Sp) = 94.98% (92.94-96.56); positive predictive value (PPV) = 96.80% (95.48-97.81); negative predictive value (NPV) = 95.91% (94.02-97.33); positive likelihood ratio (LR+) = 19.39 (13.75-27.32); negative predictive ratio (LR-) = 0.03 (0.02-0.04), and; accuracy = 96.45% (95.42-97.31). The respective positive likelihood ratio (LR+) for each of the four categories of cytopathological diagnoses (with their 95% CI) which are malignant, suspicious, benign, and nondiagnostic were 540 (76-3827); 2.69 (1.8-3.96); 0.03 (0.02-0.04); and 0.37 (0.2-0.66), respectively. In conclusion, our study demonstrates that the OSCAR procedure is a highly reliable diagnostic approach and a perfect test to select patients requiring core-needle biopsy (CNB) when performed by interventional cytopathologists in a multidisciplinary and integrated OSC setting. Besides drastically limiting the rate of nondiagnostic specimens and diagnostic turn-around time, OSCAR is an efficient and powerful first-line diagnostic approach for patient-centered care.

Distribution of breast lesions diagnosed by cytology examination in symptomatic patients at Eritrean National Health Laboratory, Asmara, Eritrea: a retrospective study

Background

Fine needle aspiration cytology is a simple, relatively accurate, non-invasive, and cost-effective method of diagnosing most breast pathologies. To date, there is no sufficient data depicting the distribution of breast lesions detected by fine needle aspiration cytology in our healthcare setting. The aim of this study was to elucidate the general distribution of breast lesions diagnosed by cytology test at Eritrean National Health Laboratory.

Methods

This retrospective study was carried out on 905 symptomatic patients between the years 2013 and 2017 at Eritrean National Health Laboratory. Diagnosis was made by fine needle aspiration cytology in patients with palpable breast lump and in some patients direct smear was prepared from a nipple discharge. Statistical analysis was carried out using Statistical Package for the Social Sciences version 23.

Results

A total of 905 patients were included in the study, of whom 871 (96.24%) were females. The age range of patients was from 13 to 93 years with mean and standard deviation of 33 ± 14.9 years. Breast lump, occurring in 892 (98.56%), was the most frequent presenting symptom. Fibroadenoma and fibrocystic breast lesions were the most prevalent lesions accounting for approximately 40% and 15%, respectively. Malignant breast lesions were seen predominantly in females above the age of 40 years with the highest frequency observed in the age range between 51 and 60 years. Pearson Chi-squared test showed significant association between patients’ age above 40 years and the risk of having a malignant breast lesion (p < 0.001). The highest number of benign and malignant breast lesions was documented in 2014 with little fluctuation elsewhere in the study period.

Conclusion

Fine needle aspiration cytology is a procedure of choice for preoperative diagnosis in breast lesions mainly in a resource-limited settings. Our study identified the occurrence of malignant breast lesions in young women, which is of a paramount public health concern. Of note, significant proportion of patients were late to seek medical attention. Therefore, enhancement of community awareness regarding breast disease and implementation of screening programs are necessary to ameliorate the morbidity and mortality associated with the disease.

International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy Cytopathology: A Review of Predictive Values and Risks of Malignancy

OBJECTIVE

We aimed to assess the risk of malignancy (ROM) and predictive values in prior breast cytology studies as a basis for the new International Academy of Cytology (IAC) Yokohama system for reporting breast fine-needle aspiration biopsy (FNAB) cytology, which classifies cytologic diagnoses into 5 categories: (1) insufficient material, (2) benign, (3) atypical, (4) suspicious of malignancy, and (5) malignant.

STUDY DESIGN

Publications between January 1, 1997, and December 31, 2017, that studied the performance characteristics of FNAB from palpable and nonpalpable breast masses were identified through the PubMed database. Data for number of total cases and cases within each diagnostic category, if available, were collected. Performance characteristics, including absolute sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and ROM for each category were recorded or, when possible, calculated.

RESULTS

The literature review resulted in a case cohort of 33,341 breast FNABs, drawn from 27 studies. Pooling these cases together, the ROM for insufficient material, benign, atypical, suspicious, and malignant were 30.3, 4.7, 51.5, 85.4, and 98.7%, respectively. The complete sensitivity and specificity were 96.3 and 98.8%, correspondingly. The PPV and NPV were 98.7 and 95.3%, correspondingly. The false-negative and false-positive rates were 3.7 and 1.0%, respectively.

CONCLUSIONS

This meta-analysis demonstrates that the diagnostic categories of the new IAC Yokohama System each carry an implied ROM, which increases from the benign to malignant categories. This study also shows the high sensitivity and specificity of FNAB for breast lesions.

Diagnostic Value of Fine-Needle Aspiration in Male Breast Lesions

OBJECTIVE

Differentiation between gynecomastia, a common cause of male breast enlargement, and breast cancer is crucial for appropriate management. Fine-needle aspiration biopsy has been shown to be sensitive and specific in assessing female breast lesions, comparable to core needle biopsy. Few such studies have been conducted in men. We assessed its diagnostic value in a male patient cohort.

STUDY DESIGN

Men who underwent fine-needle aspiration (FNA) for palpable breast lesions at Massachusetts General Hospital from January 2007 to December 2016 were evaluated. Clinical data, radiographic findings, and cytologic diagnoses of 74 breast FNA from 71 men were reviewed. Breast aspirates were classified as nondiagnostic, benign, atypical, suspicious for malignancy, or malignant. Histology was obtained in 37 cases, and clinical and radiological data were used as follow-up in 37 patients.

RESULTS

Most FNA biopsies (73%) were performed by cytopathologists, and 93.2% of the breast FNA in men were adequate; 58% showed benign processes, mostly gynecomastia (n = 22), and 28.4% (n = 21) were malignant, most often ductal carcinoma. No false-positive cytologies were obtained, and there was 1 false-negative cytology. In our study, FNA of palpable male breast lesions was 95.8% sensitive and 100% specific.

CONCLUSIONS

FNA allows sensitive, specific, and safe evaluation and diagnosis of palpable male breast lesions.

Cytological Scoring of Breast Lesions and Comparison with Histopathological Findings

Context

Cytological assessment using various morphological parameters helps segregate breast lesions in fine-needle aspiration cytology (FNAC) into different categories. The prognosis and the line of management of each category differ accordingly.

Aims

This study aims at assessing the validity of Modified Masood's Scoring Index (MMSI) by the evaluation of cytomorphological features of various breast lesions compared with histopathological findings.

Settings and Design

This is a cross-sectional study done in 65 female patients with palpable or nonpalpable breast lesions, undergoing FNAC and biopsy over a period of 18 months from December 1, 2012, to May 31, 2014.

Materials and Methods

MMSI categorizes breast lesions, based on six cytological parameters into different categories such as nonproliferative breast disease (NPBD), proliferative breast disease (PBD) without atypia, PBD with atypia, and malignancy. The findings are compared with gold standard histopathological diagnosis.

Statistical Analysis Used

Percentage of agreement, Kappa statistics, and Chi-square test.

Results

Of the total 65 cases, all cases in MMSI category I and IV showed good histopathological correlation. The agreement between MMSI and histopathology was 93.8% which is more when compared with 72.3% agreement between cytology without scoring and histopathology. MMSI has increased the diagnostic accuracy of FNAC to 93.8% from 80%.

Conclusion

The scoring system is easily reproducible, simple, and reliable. MMSI proved good histopathological correlation in category I and IV. This scoring technique has clearly demarcated those cases requiring surgical management. It is applicable for palpable and nonpalpable cases.

Adjunctive imprint cytology of core needle biopsy specimens improved diagnostic accuracy for breast cancer

Objective

Recently, therapies targeting the biological characteristics of individual cancers according to markers indicating underlying molecular biological mechanisms have become available. Core needle biopsy (CNB) is widely used, not only to diagnose, but also to determine therapeutic strategies, in patients with breast cancer. Although the diagnostic accuracy of CNB is acceptably high, false-negative results have occasionally been encountered.

Methods

The results of adjunctive imprint cytology (AIC) coinciding with CNB in 2,820 patients suspected to have breast cancer were retrospectively reviewed. The feasibility and clinical usefulness of AIC-assisted diagnosis were analyzed.

Results

Fourteen-hundred and sixty-four cases were diagnosed as not malignant using CNB alone. Forty-seven of 1464 cases were suspected to be malignant on a cytological review of AIC, and 42 were confirmed to be breast cancer on additional biopsies. The combination of CNB and AIC achieved a sensitivity of 100% (1398/1398) and a specificity of 99.6% (1417/1422). Small lesions and large noninvasive- or scirrhous-type carcinomas were the common features of the CNB-negative/AIC-positive cases.

Conclusions

Adjunctive imprint cytodiagnosis is a simple and easy procedure that assists the pathological diagnosis of breast cancer using CNB and therefore serves as a possible novel standard application.

Liquid-based cytology of the breast: pitfalls unrecognized before specific liquid-based cytology training - proposal for a modification of the diagnostic criteria

OBJECTIVES

To describe the pitfalls encountered in switching over from conventional smears (CSm) to liquid-based cytology (LBC). To explore modifications of our usual diagnostic criteria.

STUDY DESIGN

190 ThinPrep breast samples with paired biopsies were retrospectively evaluated by two breast cytopathologists experienced only in CSm. They were again studied after LBC training. The diagnostic performances were compared. In additional calculations we included those C4/suspicious samples containing 70% high-grade nuclei and up to 30% nonmalignant cells in the C5/positive category, simulating that they harbored a malignant one-cell population. We prospectively validated this modification of our diagnostic criteria.

RESULTS

Training resulted in higher complete sensitivity: 94 versus 86% (p value 0.003) and lower false negative ratio: 4 versus 12% (p value 0.003). Training generated higher complete sensitivity than collaboration without training: 94 versus 89% (p value 0.008). In the simulation, the modified criteria increased absolute sensitivity to 74% with a 0.6% false positive rate. In the validation series, they generated up to 91% absolute sensitivity, 12% suspicious rate and no false negative and false positive diagnoses.

CONCLUSION

Training in breast LBC may increase diagnostic performance. Samples containing 70% high-grade nuclei or more can be categorized as malignant.

[The "gray zone" in organized mammography screening: histocytological correlations]

The National Public Health Program has established the organized mammography screening in Hungary. The aim of this study was to conduct an audit of "gray zone" smears of the organized mammography screening in comparison with histopathological diagnoses.

METHODS

Cytology results were rated to C3 atypia probably benign and C4 suspicious of malignancy.

RESULTS

1361 women had aspiration cytology performed from a total of 47,718 mammography non-negative lesions. 105 (7.8%) were diagnosed as C3, whereas 78 (5.7) as C4. Of the 105 patients with C3 diagnosis 61 (58%) patients underwent surgical biopsy. Histology proved malignancy in 20 (32.8%) cases, and benign lesion in 41 (67.2%) cases. All (100%) of the 78 patients with C4 diagnosis had open biopsies; 69 (88.4%) cases were histologically malignant and 9 (11.6%) cases were benign lesions.

CONCLUSION

The auditing results of fine needle aspiration cytology of "gray zone" in organized mammography screening meet the proposed threshold values. Authors conclude that the "gray zone" category in breast cytology is useful and of value if used judiciously.

Fine needle aspiration cytology of breast cancer in women aged 70 years and older

AIMS

Elderly breast cancers are associated with a more favourable biological marker profile and higher proportion of specific subtypes, some of which are of low histological grade. We reviewed the fine needle aspiration cytology (FNAC) to assess the cytological characteristics and any clues to assist in the diagnosis.

METHODS

The aspirates of 140 cancers of various histological types and grades and 39 benign lesions were evaluated for 13 cytological parameters including cellularity of the direct and cytospin smears, epithelial cell clusters, cellular atypism, cytoplasmic features, vacuoles, mitotic figures, presence of myoepithelial cells, single background epithelial cells, the presence of naked nuclei, stromal fragments and necrosis.

RESULTS

We found that the presence of background single epithelial cells, atypism of such cells, absence of benign appearing epithelial fragments, nuclear atypism of the epithelial cells within the fragments, presence of moderate amount of cytoplasm of these cells, absence of myoepithelial cells within the cluster, and absence of bipolar nuclei in the background have a strong association with malignancy. Scoring only the presence of single cells in the background, single cell atypism and the absence of bipolar nuclei in a scoring system can differentiate between benign and malignant aspirates with high (>90%) sensitivity and specificity.

CONCLUSIONS

Assessing the presence of single cells in the background, single cell atypism and the absence of bipolar nuclei facilitates identification of malignancy in the aspiration of breast lesions from elderly patients.

Diagnostic accuracy of fine-needle aspiration cytology of palpable breast masses: an SROC curve with fixed and random effects linear meta-regression models

We used various meta-analytic methods to compare 25 studies describing fine-needle aspiration (FNA) cytologic analyses performed from 1984 to 2007 on palpable breast masses. We found that in the 25 studies examined, the sensitivity ranged from 78% to 100%, the specificity ranged from 76% to 100%, and the diagnostic odds ratio (DOR) ranged from 15.83 to 33 198. The overall diagnostic accuracy was found to be as follows: 0.93 (95% CI: 0.92-0.94) for sensitivity, 0.98 (95% CI: 0.97-0.98) for specificity, and 505.209 (95% CI: 273.08-934.95) for the DOR. The overall diagnostic accuracy according to the results of summary receiving operating characteristic (SROC) curve analysis was 0.95 +/- 0.0032, and the overall weighted area under the (receiving operating characteristic [ROC]) curve (AUC) was 0.99 +/- 0.0014. The DOR values did not show a large variation in the various positivity threshold values. However, the results of those studies had some heterogeneity. The four covariates that were added to the standard SROC model to evaluate variations in the results of the studies were the year of publication, the number of aspirations, the percentage of insufficient material, and the study design. The relative diagnostic accuracy of studies performed after 1990 was 3.98 times higher than that of studies performed before 1990. The relative DOR (RDOR) value was also found to be statistically significant (95% CI: 1.22-13.02). That result may be attributed to the technologic improvements in diagnostic tools over the years. Although it was not statistically significant, an increase in the number of aspirations caused an increase in the RDOR of the FNA cytology (95% CI: 0.52-8.11). In contrast, increasing the percent of insufficient material caused a statistically insignificant but clinically significant decrease in the RDOR of FNA (RDOR = 0.79, 95% CI: 0.21-2.98). In conclusion, our meta-analysis has shown that FNA cytologic analysis of palpable breast masses is highly accurate in the diagnostic differentiation of benign from malignant tumors.

p63 Immunocytochemistry improves accuracy of diagnosis with fine-needle aspiration of the breast

Breast fine-needle aspiration (FNA) is highly sensitive and specific for detecting carcinoma under most circumstances. Immunostaining for the myoepithelial cell marker p63 has been shown to be useful to separate noninvasive from invasive breast lesions in histologic examination. Its usefulness for breast FNA specimens is less certain. We performed p63 immunostains on 17 clinical samples and 29 aspirates from excised surgical specimens. One Papanicolaou-stained ThinPrep slide (Cytyc, Marlborough, MA) from each case was scored as benign, atypical, "suspicious," or positive. Cytospin (Shandon, Pittsburgh, PA) slides stained with p63 antibody were scored as to the percentage of positive single cells and percentage of positive clusters. The staining pattern of p63 was significantly different (P < .0001) between malignant and benign lesions. Based on cytology alone, the sensitivity, specificity, and positive and negative predictive values were 88%, 90%, 83%, and 93%, respectively. The application of p63 staining to specimens with a less-than-definitive diagnosis (atypical and suspicious) improved the specificity and positive and negative predictive values to 97%, 94%, and 97%, respectively. When used in conjunction with morphologic examination, p63 immunostaining may be useful to categorize cases problematic by Papanicolaou staining.

Cell blocks of breast FNAs frequently allow diagnosis of invasion or histological classification of proliferative changes

Two major limitations of breast fine needle aspiration (FNA) compared with core needle biopsies (CNB) are the inability to determine whether a cancer is invasive and to classify proliferative lesions. We studied 40 consecutive "rapid cell blocks" from breast FNAs with surgical pathology follow-up to test whether cell blocks can overcome these limitations. Of 25 carcinomas, invasion could be identified in the cell block sections in 11 (44%). One cystosarcoma phyllodes was suspected based on the cell block sections. Cell blocks from 12 of 14 benign breast FNAs showed sufficient cells to assign a histologic diagnosis of no hyperplasia (1 case, confirmed on follow-up) and usual hyperplasia (11 cases; confirmed in eight of 11 on follow-up). Specific histologic diagnoses included intraductal papilloma (2 cases), and in situ lobular neoplasia (2 cases). Cell blocks complement smears and monolayers and appear to overcome major limitations of breast FNA.

Combined use of imaging and cytologic grading schemes for screen-detected breast abnormalities improves overall diagnostic accuracy

BACKGROUND

Numeric grading systems have been validated for the reporting of mammographic abnormalities and for breast cytology. The impact of integrating lesion grades from both disciplines on the accuracy of assessment of screen-detected lesions has not been investigated.

METHODS

In the current study, all lesions were prospectively classified using the Tabar radiologic grading system, as well as the National Health Service Breast Screening Programme (NHSBSP) cytologic reporting system. For lesions assessed between January 1996 and January 2003, based on final histology or 12 months of follow-up, positive predictive values (PPV) were calculated for each imaging grade and for each cytologic grouping. After integration of the data, changes in the PPV and the negative predictive values (NPV) of cytology among lesions with varying imaging grades were tracked.

RESULTS

Data were retrieved for 4806 lesions. The differences in the rates of malignancy for lesions in the different imaging grades were significant (Grade 5, 95.8%; Grade 4, 54.6%; Grade 3, 11.6%) (P < 0.001). Similarly, the cytologic categories stratified lesions into groups with significantly different rates of malignancy (positive, 99.5%; suspicious, 89.2%; atypical, 43.4%; benign, 5.7%; inadequate, 33.3%) (P < 0.001). Integration of cytologic results with the imaging grade of lesions led to significant improvements in the PPV and NPV. Positive smears were likely to represent malignant lesions in 99.9% of Grade 5 lesions, 99.2% of Grade 4 lesions, and 95.2% of Grade 3 lesions (P < 0.0001). Similarly, negative cytology corresponded to a nonmalignant lesion in 99% of Grade 3 lesions, 81.6% of Grade 4 lesions, and in only 45.5% of Grade 5 lesions (P < 0.001).

CONCLUSIONS

The integration of numeric grading schemes for breast imaging and cytology improves the accuracy of assessment of screen-detected lesions. Because 99.9% of Grade 5 lesions with positive cytology are malignant, core biopsy confirmation may not be required in this group.

Cytomorphology of Common Malignant Tumors of the Breast

A definitive cytologic diagnosis of breast cancer is usually possible when using the six major criteria of malignancy (cellularity, dyshesion, monomorphism, anisonucleosis, irregular nuclear membranes, prominent nucleoli) as part of the triple test. Carcinomas of special type have unique clinical and cytologic features that pathologists need to consider, because these may confuse interpretation. Complete subtyping of carcinomas may not always be possible by fine needle aspiration. Diagnostic accuracy for breast carcinoma is excellent. False-negative diagnoses are infrequent and chiefly due to sampling issues. False-positive diagnoses are extremely rare. Uniform report terminology should be used to ensure that diagnostic information is conveyed appropriately and consistently to guide the next diagnostic or treatment step.

Fine needle aspiration cytology of lobular carcinoma in situ on ThinPrep®

Lobular carcinoma in situ (LCIS) of the breast is a recognized marker for increased risk of invasive carcinoma and has well-established histologic criteria. However, its detection and diagnosis on FNA of breast has not been well defined. Cytology slides (all ThinPrep) of 11 cases with biopsy-proven LCIS at Beth Israel Deaconess Medical Center were reviewed. All 11 cases showed tight and/or loosely cohesive clusters of crowded mildly enlarged nuclei and ten of 11 showed at least moderate cellularity. Single epithelial cells, small but prominent nucleoli, intracytoplasmic lumina, and two distinct epithelial-cell populations were also noted in some cases. As none of these features is specific for LCIS, it would be prudent to report such lesions as atypical so that a core biopsy or excisional biopsy will be performed before definitive treatment. The original FNA diagnosis of the 11 cases ranged from epithelial proliferation without atypia to carcinoma. Three of the 11 cases had fibroadenomas on histology with extensive involvement by LCIS. Since management for LCIS is different from that for invasive carcinoma or DCIS, it should be considered and distinguished from the latter two in cases suspicious for carcinoma on FNA.

Interobserver agreement of a probabilistic approach to reporting breast fine-needle aspirations on ThinPrep®

We have previously demonstrated the accuracy and reproducibility of a probabilistic/categorical approach for reporting breast fine-needle aspiration (FNA). However, the interobserver agreement in the application of this approach has not been assessed. Twenty breast FNA cases (each on one ThinPrep slide) were pulled from the cytology files of Beth Israel Deaconess Medical Center. The cases included benign epithelial proliferative lesions (6), DCIS (4), and infiltrating carcinoma (10), as shown by subsequent histology. Six pathologists with 14-25 yr of experience in interpreting breast FNA and 0-8 yr of experience with ThinPrep preparations rendered diagnoses according to the probabilistic approach. The kappa statistic for the unremarkable/proliferative, atypical, suspicious, and positive categories were 0.64, 0.08, 0.43, and 0.75, respectively (P < 0.001 for all except for the atypical category [P = 0.09]). Spearman's rho correlating the individual pathologist's diagnosis and the histologic diagnosis ranged from 0.51 (P = 0.02) to 0.78 (P < 0.0001). This was not correlated with the pathologists' years of experience interpreting breast FNA (P = 1.0) or with their years using ThinPrep preparations for breast FNA (P = 0.96). In conclusion, the interobserver agreement was excellent for the positive category in the probabilistic approach, poor for the atypical category, and fair to good for the other categories. The specific level of experience interpreting breast FNA or using ThinPrep among experienced pathologists did not seem to influence their accuracy in reporting the cases in our study.

Ultrasound-guided fine-needle aspiration biopsy remains a valid approach in the evaluation of nonpalpable breast lesions

The use of ultrasound-guided fine-needle aspiration (FNA) biopsy for nonpalpable breast lesions varies considerably. This retrospective study stresses the role of breast FNA in evaluating sonographically suspicious nonpalpable breast masses using a probabilistic reporting system. One hundred and eight consecutive ultrasound-guided FNA biopsies diagnosed as positive (32), suspicious (8), atypical (11), benign (55), and unsatisfactory (2) were analyzed and correlated with 61 subsequent surgical specimens. All positive cytologies showed carcinoma on histology; suspicious cases were followed by 5 carcinomas, 2 fibroadenomas, and 1 papillary lesion. Follow-up of atypical cases included 4 carcinomas, 3 fibroadenomas, and 2 papillary lesions, while all 10 biopsies following benign cytology showed fibrocystic changes. Two cases with suspicious sonographic findings but unsatisfactory cytology had lobular carcinoma. The remainder of the benign and atypical cases were followed clinically and radiographically for at least 10 months and had no evidence of carcinoma. Positive predictive values were positive, 100%; suspicious, 63%; atypical, 36%; benign, 0%. Most (40/43; 93%) carcinomas were invasive. In conclusion, ultrasound-guided FNA for nonpalpable breast lesions is highly accurate, and probabilistic reporting helps direct patient management.

Management of patients with intermediate (C3) cytology and a solitary breast lump

The records of all patients who had a C3 result on fine needle aspiration cytology (FNAC) over a 3-year period were reviewed. Clinical and mammographic findings at presentation were correlated with histopathological diagnosis. Of 43 patients, 32 patients underwent excision biopsy. Histology was benign in 25 patients, eight patients had an invasive breast carcinoma, two a phyllodes tumour and one had widespread ductal carcinoma in situ (DCIS). All but two of the patients with invasive tumours had abnormalities on clinical examination or imaging. In two patients there was no clinical or mammographic suspicion of malignancy. A C3 breast cytology result must be taken seriously as it is frequently an indicator of underlying malignancy. These results suggest that definite histology should be obtained in all patients because of the unacceptably high false-negative rate of clinical and radiological assessment in this group.

Fibroadenoma mimicking papillary carcinoma on ThinPrep of fine-needle aspiration of the breast

OBJECTIVE

To compare and contrast benign and malignant lesions of the breast that have similar appearances on fine-needle aspiration cytology and that constitute diagnostic pitfalls.

DESIGN

The cytology files (dated November 1995 through May 1998) of the Beth Israel Deaconess Medical Center were searched to identify cases of breast fine-needle aspiration biopsies that were highly cellular and composed of bland-appearing spindle/columnar cells and that could represent either epithelial or stromal cells; these cases were reported as indeterminate (atypical/suspicious) and had subsequent excisional biopsies taken.

RESULTS

Four such cases were found. Two were fibroadenomas and 2 were papillary carcinomas. Their appearances were strikingly similar on aspiration cytology. All cases were prepared with the ThinPrep method. On microscopic examination, all 4 cases were hypercellular and had many single cells and clusters of columnar/elongate cells. Immunocytochemistry proved these cells to be of epithelial origin. At least occasional bipolar stromal cells were seen in the background. The only appreciable difference between the benign and malignant cases was more significant nuclear atypia, which was barely discernible, in the malignant cases. Immunocytochemistry for smooth muscle actin was helpful in 2 cases that had sufficient material.

CONCLUSIONS

Some cases of fibroadenomas and papillary carcinomas can be very difficult, if not impossible, to distinguish on fine-needle aspiration cytology. Immunocytochemistry may be helpful if sufficient material is available. To avoid false-negative or false-positive diagnosis on cytology, it is best to report such cases as atypical or suspicious with final diagnosis pending excisional biopsy.