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

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.

Fibroadenoma of the breast; incidence of malignancy and indicators for surgical intervention: An analysis of 1392 patients

BACKGROUND

Fibroadenomas are common among young females. The size of the lesion used to be an indication for further assessment or excision. With arising of the watch and see proponents, criteria for selecting patients are important to establish.

METHODS

This is a retrospective study of a prospectively maintained database where all patients having the clinical/radiological provisional diagnosis of fibroadenoma and attending our center - from January 2008 to March 2020 - were enrolled. The primary outcome was the incidence of malignancy and the secondary outcomes were the correlation of malignancy-risk with epidemiologic and radiologic criteria.

RESULTS

The study enrolled 1392 patients. The mean age of the patients was 35.7 + ∕- 13.1 years. The median of the longest diameter of the detected breast lesions was 25 mm. The incidence of malignancy was 188 (13.5%). The size of the lesion measured by largest diameter was insignificant (p = 0.99), while the patients' age, marital status, and imaging criteria as measured by BIRADS score were significant (<0.001).

CONCLUSION

Approaching patients with the age above 35 or with BIRADS 4 provisionally diagnosed with fibroadenomas should be cautious with biopsy and short-term follow-ups The size of the tumor alone should not be used as an indication for surgical intervention.

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.