Predictors of an informative or actionable cytological diagnosis on repeat breast aspiration after an insufficient aspirate: a multicentre retrospective review.

An insufficient/inadequate diagnosis on fine-needle aspiration cytology (FNAC) of the breast is not an uncommon diagnostic dilemma. This study aims to review the rate and clinical features predicting an informative or actionable diagnosis on repeating breast aspiration after an insufficient aspirate. METHODS: Unsatisfactory/insufficient/inadequate or equivalent breast aspirates were retrieved from the involved institutions, and those with a repeat aspiration performed within 365 days were included. Clinical and radiological information were retrieved. Available cytological slides were reviewed. RESULTS: Totally 539 paired aspirates were retrieved, with 61.2% (n=330/539) and 10.9% (n=59/539) cytological diagnosis being informative (not insufficient) and actionable (not insufficient nor benign) on repeat aspiration. Younger age (p=0.005) was associated with an informative diagnosis and prior radiotherapy (p=0.097) and insufficient aspirates performed under free-hand (p=0.097) trended with an actionable diagnosis. Radiological findings of calcification (p=0.026) and hyperechogenicity (p=0.045), a small lesion size on initial (p=0.037) and repeat (p=0.059) radiological assessment and interval size increment (p=0.019) correlated with informative/actionable diagnoses. Cytomorphological parameters, except for a trend with crushing artefact (p=0.063), do not correlate with the cytologic diagnosis of the repeat aspirate. CONCLUSIONS: Repeating breast FNAC on patients after an insufficient diagnosis yields an informative ('sufficient') result in over 60% of cases. Small lesions with calcification, hyperechogenicity and/or interval size increment are more likely to yield diagnostic results on repeat aspiration and indicate select patients suitable for repeat FNAC over more invasive procedures. The lack of associations with cytomorphological parameters cautions against overinterpretation of insufficient breast aspirates.

WT1 as a myoepithelial marker: a comparative study of breast, cutaneous, and salivary gland lesions.

WT1 immunostain is expressed in various benign and malignant neoplasms, as well as normal myoepithelial cells. WT1 shows differential expression in non-neoplastic, benign, and malignant neoplastic myoepithelial cells of the salivary gland. In this study, WT1 immunostain and other myoepithelial markers were compared to investigate the value of WT1 as a myoepithelial marker, and to delineate the expression profile of WT1 in nonsalivary gland myoepithelial cells. WT1, p63, and calponin immunostains were performed on normal and lesional tissues from the breast (adenosis, sclerosing adenosis, lactating adenoma, nipple adenoma, tubular adenoma, adenomyoepithelioma, and adenoid cystic carcinoma [ACC]), skin (cutaneous mixed tumor, hidradenoma, spiradenoma, and ACC), and salivary gland (pleomorphic adenoma and ACC). The stained slides were digitized and orientated with H&E images and assessed simultaneously using QuPath. A total of 129, 58, and 56 breast, cutaneous, and salivary gland lesions, respectively, were included. There was poor agreement between WT1-p63 and WT1-calponin (κ < 0.1) in all organs, with absence of WT1 expression in normal salivary gland myoepithelium and most ACCs. There were no significant differences in WT1 expression in myoepithelial cells in normal breast tissue and benign breast neoplasms. Compared to pleomorphic adenomas, cutaneous mixed tumors showed lower WT1 expression (P < .001). WT1 is a less sensitive myoepithelial marker than calponin and p63. However, its unique pattern of expression in salivary gland primary for pleomorphic adenomas/cutaneous mixed tumor can favor a diagnosis of benign salivary gland tumors, particularly in small biopsy specimens.

Tubular Adenomas of the Breast Are Cytologically Distinct from Fibroadenomas.

INTRODUCTION: Increasing molecular evidence indicates that tubular adenoma of the breast is distinct from fibroepithelial lesions, leading to its reclassification as an epithelial tumor in the 5th World Health Organization classification of tumors of the breast. However, tubular adenoma remains poorly characterized on fine-needle aspiration cytology (FNAC) and often not distinguished from fibroadenomas. In this study, the largest cohort, to date, of histologically confirmed aspirates of tubular adenomas were reviewed and compared with aspirates of fibroadenomas. Findings from this study further define the cytological features of tubular adenoma and allow differentiation from fibroadenoma. METHODOLOGY: Aspirates of histologically confirmed tubular adenomas were reviewed for features of the background, myoepithelial, epithelial, and stromal components and then compared to a cohort of aspirates of fibroadenomas. RESULTS: Totally, 43 (tubular adenoma) and 94 (fibroadenoma) aspirates were included. Tubular adenomas displayed moderate epithelial cellularity with high cohesiveness, with stromal fragments containing epithelium. Tubules are more common in tubular adenomas (p = 0.009) and "tubular fragments" (tissue fragments containing multiple tubular structures with/without stroma) is a pathognomonic feature of tubular adenoma (p < 0.001). Calcification and fibrocystic changes were variably seen (4.65-13.5%) but without difference to fibroadenomas (p > 0.05). Cytomorphologically malignant features and mitoses were absent in all aspirates of tubular adenoma. Presence of tubules and stromal fragments were independent factors associated with tubular adenomas, whereas a predominance of large epithelial fragments and naked stromal fragments were associated with fibroadenomas. CONCLUSION: Tubular adenomas are not only histologically and molecularly separate from fibroepithelial lesions but also a distinct entity on FNAC.