The Conundrum of Papillary Breast Lesions within the C3 Category

Abstract

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.

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

“…Papillary lesions may exhibit atypical cytological features and, in the current series, 14.4% (33/229) of C3 FNACs were papillary lesions, including 30 intraductal papillomas, three papillary carcinomas and six papillomas with atypical ductal hyperplasia. Among our C3 papillary lesions, the proportion of 23.1% (9/39) atypical to malignant and 76.9% (30/39) benign was similar to other reported results 20. Within the C3 group with benign histology, intraductal papillomas were still one of the common benign lesions (18.8% (30/160)).…”

The continuing role of breast fine‐needle aspiration biopsy after the introduction of the IAC Yokohama System For Reporting Breast Fine Needle Aspiration Biopsy Cytopathology

“…26,27 The reason is that the uncertain interpretation of cytological features that may lead to an atypical diagnosis, occurs most frequently when low-risk and borderline lesions such as atypical ductal hyperplasia, atypical intraductal papillomas, or low grade phyllodes tumor are sampled (Table 5). [28][29][30] However, several studies show that even in the histological examination of limited tissue specimen as CNB samples, it may be difficult to identify these types of lesions correctly. 31,32 Remarkably, in our series, the frequency of these entities was overall very limited (50/1745, 2.9%) and the distribution of these diagnoses according to the different IAC Yokohama System categories, (Table 1) reflected the challenging microscopic assessment of their cytological features.…”

Papillary lesions of the breast: A systematic evaluation of cytologic parameters

“…There have been only a few studies 2‐6,16,17,19‐21 reporting on the various cytologic aspects of this group of lesions, and they have involved modest numbers of cases (ranging from 4 to 72) with various methodologies; this has hampered the interpretation and comparison of these series. Most studies 3‐6,16,17 analyzed biopsy‐proven papillary lesions, another 20 was based only on FNAC diagnosis without histologic correlates, and some 2,20,21 included other types of breast neoplasms. Variable features were reported, and the benign features included abundant background bipolar cells, 4‐6,21 cystic changes (accompanying apocrine metaplasia or the presence of foamy histiocytes), 4,5,17,21 background columnar cells, 4,20 and proteinaceous metaplasia 21 .…”

“…Different cytologic criteria have been suggested 2‐6,16‐21 for diagnosing and grading papillary lesions, and this lack of uniformity highlights the difficulties encountered in routine practice.…”