Inconclusive or erroneous fine‐needle aspirates of breast with adequate and representative material: A cytologic/histologic study

Abstract

Adequately cellular and representative fine-needle aspirates (FNAs) of breast have a high diagnostic accuracy. There is, however, a recognized category designated as "gray zone" where a definitive diagnosis cannot be reached. We reviewed our experience in this category to identify useful diagnostic parameters. Twenty-four such FNAs with surgical follow-up were retrieved from AUBMC files (2003-2009). Cytology slides were reviewed blindly. All cases were females, 29-73 years. There were three erroneous and 21 inconclusive diagnoses. The majority (15) was invasive adenocarcinomas: two cribriform, four tubular, one lobular, and eight not otherwise specified. The remaining cases were papillary and fibroepithelial tumors (three each), ductal carcinoma in situ, cribriform (two), and one adenomyoepithelioma (AME). Useful diagnostic features included: (1) Biphasic cell population with focal nuclear atypia and intranuclear and cytoplasmic vacuolar inclusions (AME). (2) Complex clusters of epithelial cells with cribriform architecture (cribriform carcinoma). (3) Rigid tubular epithelial structures with abrupt change in diameter, ending in pointed tips with abnormal branching (tubular carcinoma). (4) Cellular stromal fragments (fibroepithelial tumors). (5) Papillary fibrovascular cores, columnar cells, and three-dimensional papillary epithelial fragments (papillary tumors). Myoepithelial cells classically described in benign aspirates were not always a discriminatory factor. The "gray zone" in breast FNA is usually due to overlapping cytologic features of some benign and malignant lesions. Useful distinguishing cytologic features are described.

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

“…Artefact and degenerative changes may also cause atypical nuclear changes. Loss of myoepithelial cells within the epithelial cell cluster as a predictor of histological malignancy lacked discriminatory power in this study and others 25. This could be explained by the fact that, in epithelial hyperplasia and in DCIS, there was frequently expansion of the epithelial cells within the myoepithelial lined spaces, thus rendering the latter not easily visible in a smear.…”

“…This is often seen in low-grade malignancy, reported in 45% (9/20 cases) of tubular carcinoma,23 50% (4/8) of intracystic papillary carcinoma aspirates24 or in in situ or invasive cribriform carcinomas 25. One study, however, failed to demonstrate any significant association between cribriform sheets and malignancy (21.3% (30/141) of non-cancer cases vs 23.6% (21/89) of cancer cases) 22.…”

Concordance of breast fine needle aspiration cytology interpretation with subsequent surgical pathology: An 18‐year review from a single sub‐Saharan African institution

“…An additional three cases were initially interpreted as benign, with cystic (one case, 8.3%; in situ carcinoma on histology) and haemorrhagic (two cases, 16.7%; invasive carcinomas on histology) changes noted. It is well‐established that there is much overlap in cytological features used to distinguish benign from malignant breast lesions . While benign lesions typically lack epithelial dyshesion and dramatic nuclear abnormalities, cellular benign proliferations can be alarming at initial microscopic review and malignancies can be paucicellular at the time of sampling.…”

“…While benign lesions typically lack epithelial dyshesion and dramatic nuclear abnormalities, cellular benign proliferations can be alarming at initial microscopic review and malignancies can be paucicellular at the time of sampling. The importance of searching for a myoepithelial cell population, both in association with intact honeycombed sheets of epithelium and in the background as singly dispersed to coupled pairs of bipolar nuclei The importance of searching for a myoepithelial cell population, both in association with intact honeycombed sheets of epithelium and in the background as singly dispersed to coupled pairs of bipolar nuclei, remains of critical importance in discerning benign from malignant entities at breast FNAC interpretation (Figure ). Additionally treacherous is the persistence of mammary carcinoma (Figure ) within the cytomorphological differential diagnosis of many benign entities, including but not limited to fibroepithelial lesions, lactational changes and fat necrosis.…”

Interpretive Errors in Fine-Needle Aspiration of Thyroid: A 13-Year Institutional Experience in Lebanon

“…The majority of cell blocks were acellular/hypocellular and did not contribute to the study. Molecular studies are not routinely done [8].…”