Fine-needle aspiration cytology of sclerosing adenosis of the breast: a retrospective review of cytologic features in conjunction with corresponding histologic features and radiologic findings

Overcoming Pitfalls in Breast Fine-Needle Aspiration Cytology: A Practical Review

BACKGROUND

Fine-needle aspiration cytology (FNAC) is a cornerstone technique for the initial assessment of breast lesions, offering a rapid and minimally invasive option for cytological evaluation. While FNACs can forego the need for core needle biopsies (CNBs), variations in technique, subjective interpretation, and intrinsic limitations present diagnostic challenges. The International Academy of Cytology (IAC) established the Yokohama system and is developing the WHO Reporting System for Breast Cytopathology jointly with IARC, to standardize diagnostic criteria, aiming to enhance diagnostic precision and consistency. Due to the preference for CNBs, expertise in breast FNAC is low in the developed world.

SUMMARY

This review assesses common pitfalls in breast cytopathology. These common and uncommon entities may easily lead to false-negative or false-positive diagnoses, due to morphological overlap or misleading clinical and radiological contexts. For instance, pauci-cellular lesions, such as lobular carcinomas, often lead to false-negative diagnoses, whereas complex sclerosing lesions, fibroadenomas, and papillary lesions may show concerning features, resulting in a false positive. The same is true for some benign inflammatory pathologies, such as steatonecrosis, and uncommon lesions, such as collagenous spherulosis. Ductal carcinoma in situ can lead to both false-negative and false-positive diagnoses, and high-grade lesions are impossible to tell apart from invasive carcinomas. These are discussed in detail. Procedural and preanalytical conditions, and the role of ancillary testing, are also briefly addressed.

KEY MESSAGES

Breast FNAB is a powerful diagnostic technique, fast and minimally invasive. Even in contexts which lack expertise, this technique can be successfully adopted with a cautious approach and as long as pitfalls are kept in mind, benefiting patients and healthcare systems.

Immunohistochemistry Applied to Breast Cytological Material

Fine-needle aspiration biopsies (FNABs) of the breast are minimally invasive procedures enabling the diagnosis of suspicious breast lesions. Unfortunately, they are often perceived as inferior to core-needle biopsies, namely because they are supposedly unable to differentiate between high-grade ductal carcinoma in situ and invasive carcinoma or provide material for ancillary testing. Several studies have shown, however, that FNAB samples, when handled properly, are indeed capable of providing sufficient and adequate material for ancillary testing, namely immunocytochemistry (ICC). We reviewed the published literature regarding the use of ICC for both diagnostic and theranostic uses in the different types of cytological samples obtained from FNABs of the breast, including smears, liquid-based cytology samples, and cellblocks. We found that p63 and 34βE12 show promise in aiding in the differential diagnosis between in situ and invasive lesions and that most other diagnostic markers may be used as in tissue. Regarding theranostic ICC markers, results vary between publications, but with care, these can successfully be performed in cytological samples. Air-dried smears should be avoided, and cellblocks are overall more versatile than cytology slides, enabling the evaluation of not only hormonal receptors and HER2 by ICC, but also of Ki-67. Particular attention should be paid to fixation and antigen retrieval procedures in all cases. We recommend that laboratories without experience perform short validation runs before adopting these techniques into clinical practice.

Conventional and contrast-enhanced ultrasound features in sclerosing adenosis and correlation with pathology

OBJECTIVES

To evaluate the efficacy of conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) in differential diagnosis of sclerosing adenosis (SA) from malignance and investigate the correlated features with pathology.

METHODS

We retrospectively enrolled 103 pathologically confirmed SA. All lesions were evaluated with conventional US while 31 lesions with CEUS. Lesions were divided into SA with or without benign lesions (Group 1, n = 81) and SA with malignancy (Group 2, n = 22). Performance of two methods were analyzed. The ultrasonographic characteristics were compared between two groups with Student's t-test for measurement and chi-squared or Fisher's exact test for count data.

RESULTS

There were 22 lesions complicated with malignancy, and the mean age of Group 2 was higher than Group 1 (55.27 vs. 41.57, p < 0.001). The sensitivity, specificity and accuracy of conventional US and CEUS were 95.45%, 46.91%, 57.28% and 100%, 62.5%, 70.97%. Angularity (p < 0.001), spicules (p = 0.023), calcification (p = 0.026) and enlarged scope (p = 0.012) or crab claw-like enhancement (p = 0.008) in CEUS were more frequent detected in SA with malignancy.

CONCLUSIONS

Though CEUS showed an improved accuracy, the performance of ultrasound in the diagnosis of SA was limited. Awareness and careful review of the histopathologically related imaging features can be helpful in the diagnosis of SA.

Correlation of ultrasound, cytological, and histological features of 110 benign BI-RADS categories 4C and 5 nonpalpable breast lesions. The Institut Curie's experience

BACKGROUND

The purpose of this study was to determine the pathological and ultrasound (US) features of benign nonpalpable breast lesions (NPBLs) classified as Breast Imaging Reporting and Data System (BI-RADS) category 4C or 5.

METHODS

Between 2003 and 2007, 849 consecutive NPBLs detected at US and classified as BI-RADS category 4C (505) or 5 (344) initially underwent US-guided fine needle aspiration (FNA) at our institution. Benign diagnoses were established according to surgical excision findings or during a minimal 6-month imaging follow-up (mean, 3.7 years [SD, 2.6 years]). US BI-RADS features were reviewed and compared retrospectively using a chi-square test for the following pathological categories: epithelial and fibrous proliferation (EFP), cystic and papillary lesion (C&P), inflammatory lesion (IL), benign tumor (BT), intramammary lymph node (ILN), intraepithelial proliferative lesion (IPL), and nonspecific morphological alteration (NMA). The performance of FNA in the diagnosis of benignity was assessed.

RESULTS

Of 849 NPBLs, 110 (12.9%) NPBLs were benign: 88 (17.4%) were BI-RADS category 4C, and 22 (6.4%) were BI-RADS category 5. Forty-four (40%) were EFPs, 21 (19%) were C&Ps, 13 (12%) were NMAs, 11 (10%) were ILs, 11 (10%) were BTs, 8 (7%) were IPLs, and 2 (2%) were ILNs. Lesion shape, US pattern distribution, and posterior features showed statistically significant differences between these categories (P < .05): 33 (75%) EFPs exhibited posterior shadowing, 18 (86%) C&Ps were homogenous, 9 (82%) ILs were heterogeneous, 11 (100%) BTs were homogeneous, 9 (82%) BTs were oval, and 6 (75%) IPLs were irregularly shaped. Of the 110 benign NPBLs, FNA diagnosis was falsely positive in 7 (6%), suspicious in 10 (9%), and benign in 90 (82%), and 3 (3%) were inadequate for diagnosis.

CONCLUSION

A diverse array of benign NPBLs can be classified as BI-RADS category 4C or 5 on US, each showing specific imaging presentations.

Sclerosing adenosis: Ultrasonographic and mammographic findings and correlation with histopathology

The present study was conducted to evaluate the radiological findings, particularly the ultrasonographic (US) characteristics of sclerosing adenosis (SA), and their correlation with histopathological results. A retrospective review identified 191 patients with a total of 200 lesions histopathologically confirmed as SA following breast surgery between July 2009 and December 2012. Of the 191 patients, 145 (151 lesions) with SA as the major component were included for US and mammographic (MG) analysis. All 145 patients analyzed were female, with a mean age ± standard deviation of 46.8±7.8 years (range, 25-71 years). All 145 patients underwent US examination and the imaging findings included heterogeneously echogenic areas in 9.3% (14/151), masses in 51.7% (78/151), masses with calcifications in 13.9% (21/151), focal acoustic shadowing in 4.0% (6/151) and were negative in 21.2% (32/151) patients. Among the 119 lesions with visible abnormalities, 87.4% (104/119) were hypoechoic, 58.0% (69/119) were irregular in shape, 52.1% (62/119) had an ill-defined margin, calcifications were found in 17.6% (21/119) and 7.6% (9/119) were hypervascular, while none of the characteristics mentioned above were significantly correlated with histopathology. A total of 136 patients underwent MG at the Fudan University Shanghai Cancer Center, and the imaging findings included microcalcifications in 31.6% (43/136), masses in 23.5% (32/136), asymmetric focal density in 14.7% (20/136), focal architectural distortion in 22.8% (31/136), and were negative in 7.4% (10/136). The mass lesions were fewer on MG compared with US (23.5 vs. 65.6%, respectively). The area under the curve of US distinguishing between benign and malignant lesions was significantly larger compared with that of MG (0.547 vs. 0.497, respectively; P=0.036). In the 60 lesions that were overestimated by Breast Imaging Reporting and Data System US category, one or more characteristics of malignancy were found on US imaging. The most common finding of SA was masses with or without calcifications on US and microcalcifications on MG. The accuracy of US was limited, but higher compared with that of MG; however, SA mimicking the characteristics of malignancy may contribute to misdiagnosis with US.

Mammographic and Ultrasonographic Findings of Different Breast Adenosis Lesions

Aim: To describe imaging features of different breast adenosis lesions.

Materials and methods: Mammographic and ultrasonographic findings of patients with different types of adenosis were reviewed retrospectively Tissue samples were obtained either with US-guided core needle biopsy or localization with needle-wire system and surgical excision.

Results: Forty-three adenosis lesions were diagnosed in 41 patients: 27 sclerosing adenosis, 13 blunt duct adenosis and 3 microglandular adenosis. Most frequent abnormal findings of sclerosing adenosis were masses with non-circumscribed margins and focal acoustic shadowing without mass configuration (54%) on ultrasonography. Mammography was normal in 54% of sclerosing adenosis, the most common abnormality was architectural distortion (21%). In blunt duct adenosis, usually circumscribed masses (46%) were detected on ultrasonography, clustered punctate microcalcifications (23%) and circumscribed masses (23%) were observed on mammography. All microglandular adenosis lesions were non-circumscribed masses. Premalignant components were detected only with surgical excisional biopsy in three patients that showed suspicious radiological findings and benign pathological result on core biopsy.

Conclusion: The adenosis lesions have no pathognomonic characteristics on mammography and ultrasound. Total excision may be considered when suspicious radiological findings are present although core needle biopsy results are benign.

Mimickers of breast malignancy on breast sonography

The aim of this article is to review benign breast lesions that can mimic carcinoma on sonography. Cases of benign lesions mimicking carcinoma on sonography were collected among lesions that were initially assessed as suspicious on sonography according to the American College of Radiology Breast Imaging Reporting and Data System category. Sonographically guided core needle biopsy was performed, and the pathologic types were confirmed to be benign. Cases of benign lesions mimicking carcinoma on sonography were shown to include fat necrosis, diabetic mastopathy, fibrocystic changes, sclerosing adenosis, ruptured inflammatory cysts, inflammatory abscesses, granulomatous mastitis, fibroadenomas, fibroadenomatous mastopathy, and apocrine metaplasia. Benign breast lesions may present with malignant features on imaging. A clear understanding of the range of appearances of benign breast lesions that mimic malignancy is important in radiologic-pathologic correlation to ensure that benign results are accepted when concordant with imaging and clinical features but, when discordant, there is no delay in further evaluation up to and including excisional biopsy.

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.