Fibroadenoma of the breast: diagnostic pitfalls of fine-needle aspiration

Cytological features of complex type fibroadenoma in comparison with non-complex type fibroadenoma

BACKGROUND

To determine the cytomorphological features of complex type fibroadenoma (CFA), we reviewed fine needle aspiration (FNA) cytology with correlation to its histopathology findings, and compared them with non-complex type fibroadenoma (NCFA).

METHODS

From excisional biopsy or resected specimens of fibroadenoma (FA) cases treated at our institution from 2004 to 2013, we chose 46 patients who underwent FNA before a diagnosis of FA was established. We histologically re-classified them into two groups: CFA and NCFA. FNA diagnosis was retrospectively re-evaluated from FNA reports. We further re-assessed detailed characteristics of each FNA smears to identify cytomorphological features of CFA.

RESULTS

We found that 15 cases fulfilled the diagnostic criteria of CFA, in which 7 (46.7 %) had an FNA diagnosis of "suspicious for malignancy" or "indeterminate" while only 2 NCFA cases had that of "indeterminate" (p = 0.004). FNA smears from CFA cases showed discohesiveness, enlarged nuclei, prominent nucleoli, and fewer myoepithelial cells more often than NCFA. Although no significant difference was noted in patients' age and tumor size between CFA and NCFA, 5 CFA cases (33.3 %) were accompanied by the presence of carcinoma in the same breast or the contralateral breast while no NCFA cases had carcinoma in the breast.

CONCLUSIONS

FNA of CFA can lead to erroneous or indeterminate interpretation, due to proliferative and/or hyperplastic changes of ductal epithelium with or without atypia. It is important to recognize the disease entity and characteristic cytomorphological findings of CFA to reach accurate FNA diagnosis of breast lesions.

A pilot study evaluating liquid-based fine needle aspiration cytology of breast lesions: a cytomorphological comparison of SurePath® liquid-based preparations and conventional smears

OBJECTIVE

Fine needle aspiration cytology (FNAC) is recommended by the World Health Organization as a diagnostic method for breast lesions. The morphological interpretation of liquid-based preparations (LBPs) remains a diagnostic challenge due to considerably altered cytomorphology. The aim of the current study was to compare cytomorphological characteristics of SurePath® (SP)-based LBP and conventional smear (CS) in breast FNACs.

STUDY DESIGN

The study included 77 benign and 60 malignant breast FNACs obtained by both SP and CS, all with tissue confirmation. Cases analyzed with both preparations were reviewed and compared, focusing on 10 cytomorphological features.

RESULTS

SP aspirates demonstrated notable cytomorphological alterations. Among them, a prominent three-dimensional configuration of cell clusters and frequent and conspicuous nucleoli were the most prominent characteristics of SP compared with CS. Overall diagnostic performances were comparable but were slightly lower for SP than CS (diagnostic accuracy of two reviewers; 87.6 and 90.5% for SP vs. 91.2 and 92.7% for CS, respectively).

CONCLUSION

Although the reviewer should be aware of distinctive cytomorphological alterations, the SP technique is reliable for the evaluation of breast lesions with the advantage of easy interpretation and a diagnostic accuracy equivalent to CS.

Indeterminate and erroneous fine-needle aspirates of breast with focus on the 'true gray zone': a review

OBJECTIVE

To review our experience and the literature on inconclusive/erroneous fine-needle aspirates (FNAs) of breast with the focus on the 'true gray zone'. To describe the cytology, differential diagnosis, pitfalls and limitations of common and rare lesions.

STUDY DESIGN

We conducted a literature search focusing on breast FNAs with statistical data of C3 and C4 categories including false-positive and false-negative cases. Similar data from 2003 to 2009 was obtained from our institution.

RESULTS

C3 and C4 categories account for 3-17% of breast FNAs. Contributing factors are technical difficulties, inexperienced pathologists interpreting FNAs of breast and overlap of cytologic features of certain benign and malignant conditions; this last, 'true gray zone' accounts for 2% of cases. Fibroadenoma, proliferative breast lesions, gynecomastia, infiltrating and in situ low-grade adenocarcinomas and tubular, cribriform, lobular and mucinous carcinomas are the most common problematic lesions. Granular cell tumor, adenomyoepithelioma, pregnancy-related lesions, fat necrosis, inflammatory and radiation changes, adenoid cystic carcinoma, spindle-cell lesions and Phyllodes tumor are less common.

CONCLUSION

Inconclusive/erroneous FNAs of breast due to the 'true gray zone' are rare. Most are due to the overlapping cytologic features of some benign and malignant conditions. Practical features that may help arrive at the correct diagnoses are elucidated.

Fine-needle aspiration of gray zone lesions of the breast: fibroadenoma versus ductal carcinoma

While breast lesions have characteristic cytological features, some lesions, particularly adenocarcinoma and fibroadenoma, may present with overlapping features causing erroneous diagnoses. The current study aimed to define significant cytomorphologic features predictive of fibroadenoma and adenocarcinoma, respectively. Further, we intended to evaluate the predictive characteristics for differentiation between gray zone lesions and to identify root causes contributing to misdiagnoses. First, direct smears prepared from 14 histology-confirmed fibroadenomas and 14 adenocarcinomas were reviewed and characteristics of commonly encountered morphologic features were assessed. We then retrospectively and blindly reviewed nine cytohistologic discrepant cases using the significant characteristic as a guideline, in order to assess whether these discrepant cases could be correctly categorized. Morphologic characteristics predictive of fibroadenoma included moderate cellularity, large, folded cellular sheets/aggregates, staghorn projections, smooth and round borders, monolayers, honeycomb arrangement, smaller nuclear size, and background bipolar cells. Predictive characteristics of adenocarcinoma included high cellularity, loose cohesive sheets/aggregates, pointed projections, irregular borders, larger nuclear size, irregular nuclear membrane, prominent nucleoli, and single atypical epithelial cells. Retrospective, blind review correctly re-classified seven out of nine cytohistologic discrepant cases, including five false negative cases and two false positive cases. Root causes contributing to the misdiagnoses were large branching sheets of carcinoma mimicking folded sheets of fibroadenoma; fibroblasts mimicking myoepithelial cells; apocrine cells mimicking carcinoma cells; and not recognizing the loose myxoid matrix presenting as soap bubbles in fibroadenoma. In conclusion, this study identified significant characteristics that can assist in achieving accurate diagnosis in a subpopulation of breast aspirates that present with overlapping features.

Identification of components of fibroadenoma in cytology preparations using texture analysis: a morphometric study

OBJECTIVES

To evaluate the utility of image analysis using textural parameters obtained from a co-occurrence matrix in differentiating the three components of fibroadenoma of the breast, in fine needle aspirate smears.

METHODS

Sixty cases of histologically proven fibroadenoma were included in this study. Of these, 40 cases were used as a training set and 20 cases were taken as a test set for the discriminant analysis. Digital images were acquired from cytological preparations of all the cases and three components of fibroadenoma (namely, monolayered cell clusters, stromal fragments and background with bare nuclei) were selected for image analysis. A co-occurrence matrix was generated and a texture parameter vector (sum mean, energy, entropy, contrast, cluster tendency and homogeneity) was calculated for each pixel. The percentage of pixels correctly classified to a component of fibroadenoma on discriminant analysis was noted.

RESULTS

The textural parameters, when considered in isolation, showed considerable overlap in their values of the three cytological components of fibroadenoma. However, the stepwise discriminant analysis revealed that all six textural parameters contributed significantly to the discriminant functions. Discriminant analysis using all the six parameters showed that the numbers of pixels correctly classified in training and tests sets were 96.7% and 93.0%, respectively.

CONCLUSION

Textural analysis using a co-occurrence matrix appears to be useful in differentiating the three cytological components of fibroadenoma. These results could further be utilized in developing algorithms for image segmentation and automated diagnosis, but need to be confirmed in further studies.

Fine-needle aspiration cytology of mammary fibroadenoma: a comparison of ThinPrep® and cytospin preparations

Mammary fibroadenoma (FA) is a lesion frequently sampled and diagnosed by fine-needle aspiration (FNA). Accurate cytologic diagnosis of this common benign lesion is important as this can lead to non-surgical, conservative management when breast imaging and clinical examination are concordant. In most instances, a confident diagnosis of FA is possible because of a characteristic cytologic appearance that includes hypercellularity, large epithelial cell groups, staghorn epithelial configurations, stromal fragments, and numerous background stripped nuclei. Nevertheless, FAs can be diagnostically challenging because of shared cytomorphologic features with other benign lesions and low-grade carcinoma. As such, FA is a well-recognized source of false results on FNA cytology. Furthermore, there are reports that newer thin layer cytopreparatory techniques, including the ThinPrep® (TP) system (Hologic Corp., Bedford, MA), alter the appearance of FA on FNA compared to conventional preparations and may compromise accurate cytologic diagnosis.

Mastopathic fibroadenoma of the breast: a pitfall of aspiration cytology

OBJECTIVE

To assess the correlation between cytological diagnoses and histological subtypes of fibroadenoma (FA) and to clarify the cytological features of a specific group of FA displaying variable features similar to fibrocystic disease (mastopathic type, MFA), and to evaluate the significance of this subtype in cytological diagnosis.

METHODS

A review of 141 cases of histologically proven FA was performed. We re-classified them into four subtypes according to Kinoshita's criteria [Jpn J Breast Cancer6 (1991) 377] and further selected 92 cases for which both fine needle aspiration (FNA) smears and histological specimens were available. Among them, 18 cases of MFA and their cytological smears were selected for the present study.

RESULTS

There was significant correlation between MFA and cytological diagnosis of 'indeterminate' or 'suspicious for malignancy' (P < 0.01). Although no false-positive diagnosis was experienced in our series, 56% of the MFAs (10/18) had cytological diagnoses of indeterminate or were included in the category 'suspicious for malignancy'. Smears from MFA revealed high cellularity (9/18 smears had more than 10 epithelial clusters each composed of more than 50 cells), presence of cellular discohesiveness (13/18, 72.2%), but only mild nuclear atypia (5/18, 27.8%). Anisonucleosis was present in fewer than half the cases and no apparent condensed chromatin was identified.

CONCLUSION

We highlight the significance of subclassification of MFA in aspiration cytology of breast. MFA had a significantly higher chance of falling into the 'suspicious for malignancy' or 'indeterminate' diagnostic category in aspiration cytology. It might be a diagnostic challenge for cytopathologist to identify this subtype of FA in FNA smears.

FNA of breast fibroadenoma: observer variability and review of cytomorphology with cytohistological correlation

OBJECTIVE

To determine the observer variability in reporting fibroadenoma of the breast by fine needle aspiration (FNA) and to review the cytomorphological features of the lesion with cytohistological correlation.

METHODS

Retrospective analysis of FNA smears from 110 cases diagnosed as fibroadenoma of which surgical pathology follow-up was available in 33. Two pathologists were asked to categorize smears from 67 cases of breast lesions while blinded to the clinical finding as fibroadenoma, epithelial hyperplasia (usual and atypical) and malignant. All fibroadenoma (33) and cancer (15) cases were biopsy-proven. The same set of slides was re-circulated to one of the pathologists, and his first and second round results were compared.

RESULTS

Pre-review cytohistological correlation was attained in 32 of 33 cases of fibroadenoma (97%). The overall agreement between the two observers was 87% [Kappa = 0.74, 95% confidence interval (CI) 0.72-0.76]. Cytohistological correlation was achieved in 26 of 33 (79%) cases. Intra-observer agreement was 91% (Kappa = 0.82, 95% CI 0.89-0.93) with cytohistological correlation in 29 of 33 (87%) cases. Causes of diagnostic errors included marked dissociation, pleomorphism, poorly cellular smears from hyalinized fibrodenoma, lacational changes and apocrine metaplasia with cystic changes. Multinucleated giant cells were frequently encountered in FNA smears from fibroadenoma (31.8%), but in none of the lumpectomy specimens. Their histiocytic nature was suggested by immunohistochemistry.

CONCLUSION

FNA was a highly sensitive method for the diagnosis of fibroadenoma. Current cytological criteria were reliable and gave high inter- and intra-observer reproducibility.

Can hamartoma of the breast be distinguished from fibroadenoma using fine-needle aspiration cytology?

In an attempt to determine if it is possible to distinguish hamartoma of the breast from fibroadenoma using fine-needle aspiration cytology, we reviewed the cytological slides of 13 histopathologically confirmed cases of hamartoma of the breast and compared them with the cytological features of 13 histologically confirmed fibroadenomas. In each case, we studied the epithelial and stromal features. Cytologic characteristics were retrospectively evaluated in a semiquantitative manner. In conclusion, the finding of intact lobular units and a relative paucity of stroma may suggest the diagnosis of hamartoma.

Fine needle biopsy cytology of breast lesions: a review of interpretative difficulties

Screening mammography and greater community awareness of breast carcinoma have led to an increase in fine needle biopsies of the breast. As a consequence, a wide variety of cytologic patterns have been encountered and studied in benign, proliferative, and malignant breast lesions. We review the main reasons for diagnostic difficulties in breast cytology, the situations in which either a false positive or a false negative diagnosis is possible, as well as conditions whose incorrect typing can lead to inappropriate management.

'Atypical' and 'suspicious' diagnoses in breast aspiration cytology

BACKGROUND

In 1996, the National Cancer Institute (NCI) recommended five categories for the diagnosis of breast aspiration cytology: benign, atypical, suspicious, malignant, and unsatisfactory. The authors evaluated the usefulness of separating inconclusive diagnoses into the aforementioned atypical and suspicious categories. The current study examined the correlation between cytologic and histologic findings made in breast aspiration cytology specimens that were categorized in accordance with these NCI guidelines.

METHODS

From 1992 to 2000, 7727 breast aspirations were performed at the University of Miami/Jackson Memorial Medical Center (Miami, FL). Aspirates were classified using criteria similar to the NCI recommendations. Four hundred eighty-nine aspirates (6%) were classified as being cytologically 'atypical' or 'suspicious'. Of those, 225 'atypical' aspirates and 162 'suspicious' aspirates had available histologic follow-up data and were included in the study.

RESULTS

Among the 'atypical' aspirates, 118 (52%) yielded malignant findings on histologic evaluation. Infiltrating ductal carcinoma (n = 87; 74%) was the most common malignant diagnosis, followed by infiltrating lobular carcinoma (n = 12; 10%). Among 'suspicious' aspirates, 135 (83%) yielded malignant findings on histologic analysis. The most common benign diagnosis in both 'atypical' and 'suspicious' aspirates was proliferative fibrocystic changes with or without atypia, followed by fibroadenoma.

CONCLUSIONS

Most aspirates that yielded suspicious findings on cytologic examination proved to be malignant, as did > 50% of aspirates that yielded atypical findings. Infiltrating lobular carcinoma commonly was underdiagnosed as being atypical on cytologic examination. Benign lesions with atypical or suspicious cytologic diagnoses included certain cases of atypical ductal hyperplasia. The authors concluded that the distinction between the atypical and suspicious categories, as recommended by the NCI, is not warranted. Therefore, they suggest the use of a single term, such as 'equivocal', to describe inconclusive diagnoses on breast fine-needle aspiration cytology.

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.

Atypical squamous metaplasia of seromas in breast needle aspirates from irradiated lumpectomy sites: a potential pitfall for false-positive diagnoses of carcinoma

The presence of squamous metaplasic cells is an uncommon finding in fine-needle aspiration (FNA) biopsies of the breast. We report that FNA smears containing atypical squamous metaplastic cells derived from the lining of seroma-type cavities following lumpectomy and irradiation in patients with breast cancer can be a potential pitfall for a false-positive diagnosis of recurrent malignancy. Four fine-needle breast aspirates from two adult patients with previous histories of invasive breast carcinoma were retrieved. One specimen was from a 56-yr-old female, while the remaining three FNAs aspirates were from a 75-yr-old female. Both patients presented with indurated cystic lesions arising at irradiated lumpectomy sites. The cytospins from the 56-yr-old patient showed markedly atypical cells having enlarged, degenerating, hyperchromatic nuclei and surrounding dense cytoplasm with sharp borders that were suspicious for carcinoma. A mastectomy revealed irradiation changes and atypical squamous metaplastic cells lining a cystic cavity consistent with a seroma, but there was no evidence of residual cancer. After three aspirations yielded "atypical" diagnoses, the second patient underwent core needle biopsies that also revealed changes consistent with a seroma cavity lined by atypical squamous metaplastic cells. We believe this is the first report of squamous metaplasia occurring in a seroma cavity following lumpectomy and irradiation of the breast. The squamous metaplastic cells in aspirates of these cystic lesions may display significant cellular atypia that can potentially result in a false-positive diagnosis of malignancy.

Fibroadenomas with atypia: causes of under- and overdiagnosis by aspiration biopsy

Fibroadenoma (FA) is a common benign breast lesion frequently sampled by fine-needle aspiration biopsy (FNAB). Although the cytologic diagnosis is straightforward in most cases, cellular discohesion and atypia in FAs may lead to falsely atypical or positive FNAB diagnoses. Conversely, some adenocarcinomas mimic a fibroadenomatous pattern on FNAB, resulting in a false-negative diagnosis. We reviewed the cytologic and histologic findings in 25 cases with a preoperative FNAB diagnosis of FA, wherein excision was recommended based on atypia. Our aim was to analyze the spectrum of changes causing under- or overdiagnosis in such cases. The smears were assessed for cellularity, cellular discohesion, presence of dissociated intact cells and nucleoli, nuclear pleomorphism, oval bare nuclei, and stromal fragments. The histologic findings were correlated with FNAB features. At excision, 88% of FAs classified as atypical on FNAB were benign (FA with ductal hyperplasia and lactational change, myxoid FA, and other fibroepithelial lesions). Differentiating myxoid FA from colloid carcinoma was difficult due to the abundance of extracellular mucin in which the dissociated epithelial cells were floating. Two (8%) cases were carcinomas on excision; the reasons for underdiagnosis in one case reflected sampling, and in the other, interpretative error. There was one (4%) benign phyllodes tumor which lacked stromal fragments and single stromal cells on FNAB smears. The lesion was called atypical, based on the epithelial discohesion on the smears. We conclude that the majority of FAs with atypia on FNAB are benign lesions. Considering the grave consequences of a false-positive cytologic diagnosis, we recommend a conservative approach in interpreting FNAB smears which overall display a fibroadenomatous pattern.

False-positive reports in fine needle biopsy of breast lesions

A review of the literature reveals considerable variations in the diagnostic accuracy of fine needle biopsy (FNB) of breast lesions between series, partly due to different methods of calculation, different definitions, and insufficient numbers of cases with adequate follow-up to provide reliable statistics. The best larger series have a false-positive rate between 0.2 and 0.3%, slightly higher for non-palpable than for palpable lesions. The cytological patterns of a range of benign lesions which may cause diagnostic difficulties and may be misdiagnosed as malignant by FNB are described, and guidelines to reduce the risk of false-positive diagnoses are proposed.

Critical clinicopathologic analysis of 23 cases of fine-needle breast sampling initially recorded as false-positive. The 44-year experience of the Institut Curie

BACKGROUND

Because false-positive cytologic diagnoses in breast tumors are rare, few cases have been reported, although their consequences may be highly detrimental to the patient. The authors report the Institut Curie's experience, by using a multidisciplinary approach.

METHODS

Of 9334 benign breast tumors examined preoperatively for cytologic diagnosis by fine-needle sampling (FNS), the 23 (0.25%) FNS cases considered to be false-positive were retrospectively reviewed and analyzed.

RESULTS

Tumors were situated close to the nipple in 7 cases and away from the nipple in 16 cases. Tumor stage was T0 for 1 case, T1 for 18 cases, and T2 for 4 cases. Radiologically, six tumors were classified as malignant, seven as indeterminate or suspicious, and nine as benign. Three of six tumors studied by flow cytometry were DNA aneuploid. Based on a multidisciplinary clinicopathologic review, 20 FNS cases were finally classified as false-positive, and the remaining 3 tumors with malignant FNS and subsequent benign histology were classified as true-positive, because local and/or metastatic progression was observed in the short term.

CONCLUSIONS

The authors' review suggests two categories of false-positive cases: the first in which cytologic benign patterns are overdiagnosed, and the second in which atypical morphologic criteria were present. Nevertheless, as shown by the malignant course in three cases, patients with malignant preoperative FNS and corresponding benign histology always require close clinical follow-up. Finally, surgical overtreatment rate could be decreased if all radiologically benign tumors with positive/suspicious FNS were subject to intraoperative frozen section examination.

Cytohistologic features of invasive micropapillary carcinoma in a young female

Invasive micropapillary carcinoma (IMPC) is a recently reported variant of breast carcinoma in women. There has been only a single report describing the cytologic features of IMPC in the literature. We report on the cytohistologic features of IMPC with diffuse involvement of two quadrants of the breast and axillary lymph node metastases in a 32-yr-old female. The cytologic appearance of IMPC was characterized by high cellularity, marked cell discohesion, and epithelial cells forming aggregates, morules, and angular and papillary clusters without fibrovascular cores and showing high nuclear/cytoplasmic ratio, irregular nuclear contours, and finely stippled chromatin. Occasional psammoma bodies were noted. Histologic examination showed a pure IMPC composed of clusters, morules, and aggregates of malignant epithelial cells surrounded by distinctly clear spaces separated by thin fibrovascular septa. The tumor involved both inner quadrants and axillary lymph nodes. A primary tumor elsewhere, particularly in the ovaries, was excluded. The patient has been disease-free 38 mo after the initial diagnosis.

Breast carcinoma in a fibroadenoma: diagnosis by fine needle aspiration cytology

We describe a case of ductal carcinoma in situ (DCIS) occurring in a fibroadenoma diagnosed by fine needle aspiration (FNA) cytology. The cytological features comprised a small population of pleomorphic cells admixed with a dominant population of bland epithelial cells showing features consistent with those of a fibroadenoma. Excision biopsy confirmed the presence of DCIS within an otherwise typical fibroadenoma. Recent reviews have emphasised the potential for fibroadenoma to cytologically mimic carcinoma, leading to false positive findings, however the converse is also possible. We conclude that a false negative cytological diagnosis may be avoided by recommending histological confirmation by excision biopsy when significant atypia is present, even if the overall pattern is that of a fibroadenoma.

Diagnostic significance of 'benign pairs' and signet ring cells in fine needle aspirates (FNAs) of the breast

Most breast mass lesions are readily characterized by FNA with cytodiagnosis. Occasionally, benign but markedly proliferative lesions are diagnostically difficult to separate from well differentiated malignancies. We present information pertaining to the diagnostic significance of two cytologic findings observed in breast aspiration specimens, namely pairs of stripped bipolar nuclei and signet ring cells (SRC). We have evaluated aspirate smears from 219 cases of histologically proven benign (n = 114) and malignant (n = 105) breast lesions. Both singlets and pairs of bipolar nuclei and SRC were enumerated, and their numbers were correlated to histological diagnosis. Closely associated pairs of stripped bipolar nuclei were found in 68% of benign lesions compared with only 3.8% of carcinomas, establishing their presence as a highly specific indicator of a benign process. Large numbers of such 'benign pairs' also favoured the diagnosis of fibroadenoma. SRC were identified in 66% of histologically proven carcinomas (67% of ductal and 70% of lobular). SRC were also present in 10% of histologically benign cases. In the malignant cases, SRC were most frequently noted in a single cell distribution or within small, loosely cohesive tissue fragments. In the benign instances, SRC were most commonly noted within large fragments, and many of these cells were proved by immunohistochemical reactions to be vacuolated myoepithelial cells. We conclude that the presence of bipolar nuclei in closely associated pairs suggests benignity and aids in the subclassification of benign breast masses. In addition, the presence of SRC does not aid in the classification of tumour subtype (ductal vs lobular), and the occurrence of such cells in the proper context should prompt surgical biopsy.

Fine-needle aspiration is limited in the classification of benign breast diseases

Fine needle aspiration (FNA) has been proven to be accurate for the detection of breast carcinomas. However, its utility in the classification of benign breast lesions is less clear. We therefore undertook a study of 76 adequate preoperative FNAs of the breast from patients whose surgical biopsies of the breast were shown to be benign (18 nonproliferative diseases, 30 fibroadenomas, 19 proliferative breast diseases without atypia, and 9 proliferative breast diseases with atypia). A number of architectural and cellular features on cytology were evaluated. Histology slides were also reviewed. Both cytology and histology specimens were categorized as nonproliferative disease, fibroadenoma, proliferative breast disease without atypia, and proliferative breast disease with atypia. There was exact diagnostic correlation between cytology and histology in only 42 (55%) of the 76 cases. No cellular or architectural features on FNA examined correlated with the presence of epithelial proliferation on histology. The presence of two epithelial cell populations (one unremarkable and one atypical), small but prominent nucleoli, and nuclear pleomorphism on FNA significantly correlated with the presence of atypia on histology. However, these features are also present in breast lesions without proliferation or atypia, and are not diagnostic of atypical proliferative lesions of the breast. Therefore, FNA of the breast is limited in classifying benign breast diseases.

Stereotactic fine-needle aspiration biopsy for the evaluation of nonpalpable breast lesions: report of an experience based on 2,988 cases

BACKGROUND

The increasing use of mammography has led to a significant increase in the detection of clinically occult lesions, the majority of which prove to be benign. SFNB has been suggested as a means of expediting a diagnosis for lesions that are malignant while limiting surgical biopsies for those that are benign.

METHODS

Clinically occult mammographic lesions were assessed by SFNB in 2,988 patients. Definitive histologic diagnoses were made on surgical specimens in all instances in which the cytologic diagnosis was malignant, suspicious, or atypical. Patients with benign cytology were either followed with interval mammograms or underwent surgical biopsy.

RESULTS

Two hundred ninety-one of the 295 lesions (99%) diagnosed as cancer via SFNB were confirmed by histopathology. Twenty-two of the 22 lesions (100%) that were diagnosed as suspicious were diagnosed on histopathology as malignant. Forty-three of the 70 lesions (61%) with cytologic atypia were diagnosed on histopathology to be malignant.

CONCLUSIONS

SFNB is an accurate means of diagnosing carcinoma, but must be followed by surgical biopsy when the cytology shows atypia. For lesions diagnosed as benign by SFNB, close interval mammography is essential.

Fine-needle aspiration cytology of ductal hyperplasia with and without atypia and ductal carcinoma in situ

To determine cytomorphological characteristics of proliferative lesions of breast duct epithelium, we reviewed fine-needle aspiration (FNA) smears of 11 cribriform and micropapillary, low nuclear grade, ductal carcinomas in situ (DCIS), nine atypical ductal hyperplasias (ADH), and 10 florid or moderate ductal hyperplasias (DH) without atypia. These breast lesions presented as a palpable mass in 16 patients or were detected by diagnostic imaging in 14 patients. Cytological findings evaluated were cellularity, cell composition, architectural pattern (including presence and shape of intercellular spacing and cell characteristics of epithelial cell groups), nuclear diameter and pleomorphism, chromatin pattern, and number of single epithelial cells. Smears also were evaluated by cytological criteria only, using the scoring system of Masood et al. Based on our study's use of cytological and architectural features combined, the FNA diagnoses were as follows: of the 11 DCIS cases eight were carcinoma and three were inconclusive: proliferative epithelium (ADH v DCIS); of the nine ADH cases two were carcinoma and seven were inconclusive: proliferative epithelium (ADH v DCIS); and of the 10 DH cases four were DH, two were suspicious for carcinoma, and four were inconclusive: proliferative epithelium (DH v ADH). Using the cytological scoring system alone, of the 11 DCIS cases one was classified as carcinoma, five as ADH, and five as DH; of the nine ADH cases one was classified as carcinoma, three as ADH, and five as DH; and of the 10 DH cases four were classified as ADH and six as DH. This study shows that the application of both cytological and architectural criteria to the interpretation of FNA smears is more reliable than cytology alone in the identification of proliferative breast lesions and low-grade carcinoma. However, overlapping features between DH and ADH as well as ADH and low-grade carcinoma exist making separation of some of these lesions difficult. Aspirates of DH and ADH may display many single epithelial cells, mimicking low-grade carcinoma. However, a diagnosis of low-grade carcinoma can be made with confidence if the aspirates are cellular with many single atypical epithelial cells and lack an admixture of benign cellular elements. Architectural and cytological characteristics of proliferative duct epithelium, as evaluated in histological sections, are well represented in aspiration smears and should aid in the identification of these lesions.

Fine-needle aspiration cytology of mammary adenomyoepithelioma: report of a case with intranuclear cytoplasmic inclusions

Adenomyoepithelioma of the breast is an uncommon lesion which may recur and rarely metastasizes. We report the fine-needle aspiration (FNA) findings in one case of mammary adenomyoepithelioma in which this tumor's unusual cytomorphology led to a cytologic diagnosis of malignancy, possible metastatic to the breast. Large, atypical, polygonal cells, some with intranuclear cytoplasmic inclusions, were most worrisome cytologically, but corresponded in the biopsied specimen to cells immunohistochemically documented to be of myoepithelial origin. Nests of epithelium and myoepithelial cells sometimes embedded in fibrous, stromal fragments were suggestive of an infiltrating pattern. Recognition of such unusual features in breast FNA is most important since definitive therapy may follow an FNA diagnosis of carcinoma in some clinical settings. In cases with unusual morphology, surgical biopsy should be recommended to clarify the nature of the lesion.