The true nature of atypical breast cytology

Atypical aspirates of the breast: a dilemma in current cytology practice

Aims

The probabilistic approach is widely adopted for breast fine needle aspiration cytology. However, a definite cytological diagnosis is not always possible for C3 (atypia) cases, which poses a management dilemma as this represents a mixed category of benign and malignant cases. It would be beneficial to be able to predict malignancy based on specific cytological features in C3 aspirates.

Methods

A comprehensive panel of cytological features (including quantitative, cytomorphological and background features) in a large cohort of C3 breast aspirates with subsequent histological excisions was evaluated to identify relevant morphological criteria predicting the risk of subsequent malignancy.

Results

A total of 229 C3 specimens with histological follow-up were included. Malignant outcome was found in 30.1% of specimens and the majority were invasive cancers. Features that showed a significant association with malignant outcome included older age (p=0.001), lower percentage of epithelial cell clusters and high percentage of single cells (p=0.002), cribriform architecture in cell clusters (p=0.034), presence of intracellular mucin (p=0.027), increased cell clusters without myoepithelial cells (p=0.048), diminished fibromyxoid stromal fragments (p=0.001), reduced bipolar nuclei (p=0.021) and the presence of necrosis (p=0.023). Except for the percentages of single cells and cell clusters without myoepithelial cells, all other features were shown to be independent risk predictors in multivariate analysis.

Conclusions

C3 aspirates were associated with a significant probability of histological malignancy. Certain quantitative, cytomorphological and background features were potentially helpful in predicting the risk of a malignant outcome. The prediction could be clinically useful in the management of C3 cases.

Modified Core Wash Cytology: A reliable same day biopsy result for breast clinics

BACKGROUND

Fine Needle Aspiration Biopsy (FNAB), Core Needle biopsy (CNB) and hybrid techniques including Core Wash Cytology (CWC) are available for same-day diagnosis in breast lesions. In CWC a washing of the biopsy core is processed for a provisional cytological diagnosis, after which the core is processed like a regular CNB. This study focuses on the reliability of CWC in daily practice.

METHODS

All consecutive CWC procedures performed in a referral breast centre between May 2009 and May 2012 were reviewed, correlating CWC results with the CNB result, definitive diagnosis after surgical resection and/or follow-up. Symptomatic as well as screen-detected lesions, undergoing CNB were included.

RESULTS

1253 CWC procedures were performed. Definitive histology showed 849 (68%) malignant and 404 (32%) benign lesions. 80% of CWC procedures yielded a conclusive diagnosis: this percentage was higher amongst malignant lesions and lower for benign lesions: 89% and 62% respectively. Sensitivity and specificity of a conclusive CWC result were respectively 98.3% and 90.4%. The eventual incidence of malignancy in the cytological 'atypical' group (5%) was similar to the cytological 'benign' group (6%).

CONCLUSION

CWC can be used to make a reliable provisional diagnosis of breast lesions within the hour. The high probability of conclusive results in malignant lesions makes CWC well suited for high risk populations.

The Conundrum of Papillary Breast Lesions within the C3 Category

OBJECTIVES

To identify features that could define papillary ductal cell proliferation within the C3 category and to subcategorise papillary lesions into benign papillomas which can be managed conservatively and atypical/malignant papillary neoplasms which require surgical intervention.

STUDY DESIGN

A blind microscopic rescreen of all C3 cases was conducted. The corresponding histological outcome was compared with the cytology. Statistical analysis was performed using papillary versus non-papillary outcomes and benign versus atypical/malignant papillary lesions. In addition, macropapillary lesions (papilloma and encysted papillary carcinoma) were plotted against micropapillary ductal carcinoma in situ.

RESULTS

Two hundred thirty FNA cases reported as C3 included 72 papillary neoplasms (52 benign papillomas and 20 atypical/malignant papillary lesions). Features specific to papillary lesions within C3 include macropapillary fragments, complex sheets, palisading strips, cystic background, cohesion and a decreased nuclear-to-cytoplasmic ratio. Features favouring atypical/malignant papillary lesions include decreased numbers of bare bipolar nuclei, discohesion and a non-cystic background. These features are common to most breast malignancies; however, identification of papillary features often results in a downgraded diagnosis from C5.

CONCLUSIONS

This study supports the ability to reliably identify papillary ductal cell proliferation within C3. Certain features can distinguish papillary lesions from other C3 pathologies. This separation is likely to be clinically useful as papillary lesions may require a different management approach.

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.

What should not be reported as atypia in urine cytology

The term "atypia," although not well characterized, is widely used in diagnostic surgical and cytopathology. Because there are no guidelines regarding when to use this term, in the majority of cases, it is used as a "wastebasket." This definitely applies to urine cytology, where the reported rate of atypia ranges from 1.9% to 23%. This review lists a number of cytomorphologic findings in urine cytology that are associated with known and specific causes. Urine specimens in which the morphologic changes can be attributed to particular etiologic factors should no longer be classified as "atypical." These include urine specimens showing reactive umbrella cells or seminal vesicle cells, reactive changes due to stones, cytologic changes characteristic of infectious processes or therapy effect, instrumented urines with pseudopapillary clusters, and urinary diversion specimens.

The microscopic complexities of C3 in breast cytology

BACKGROUND

Fine-needle aspiration (FNA) of difficult breast lesions often results in an atypical (C3) report. The assortment of outcomes generated by C3 reports varies widely, and this has given rise to different clinical management pathways.

OBJECTIVE

To identify and objectively assess microscopic features associated with atypical/C3 breast FNA cases.

MATERIALS AND METHODS

A total of 230 atypical breast FNAs were subjected to a blind microscopic rescreen using a range of robust qualitative and quantitative cytological criteria including cellularity, architectural qualities, cytomorphology and background features. A logistic regression with a receiver operating characteristic (ROC) curve and the resultant forward stepwise analysis were conducted to assess the results. This statistical testing was measured against malignant, benign proliferative and benign non-proliferative outcomes.

RESULTS

The malignant and benign proliferative outcomes showed a mixture of opposing protective and predictive individual cytological criteria. The stepwise analysis produced models demonstrating the best combination of individual cytological criteria for malignancy, proliferative and benign non-proliferative entities. In the malignancy model, discohesion, nuclear crowding within sheets, diminished numbers of bare bipolar nuclei and myoepithelial cells, the presence of tubules or necrosis and the absence of a cystic background were important features. The benign proliferative model suggested the same criteria but with the opposite implication and with the addition of several others, such as the presence of apocrine metaplasia, retained polarity and a speckled or coarse chromatin pattern. Age was a significant factor in malignant and proliferative outcomes. The benign non-proliferative stepwise analysis produced a model with fewer criteria (complex sheets, bare bipolar nuclei and a cystic background) limiting clinical application.

CONCLUSION

Atypical/C3 breast cytology remains a legitimate reporting category. However, it is associated with a number of different histological outcomes. The incidence of the C3 category can be significantly reduced by controlling extrinsic factors and understanding the associated microscopic features.