Hormone receptor and HER2 assessment in breast carcinoma metastatic to bone: A comparison between FNA cell blocks and decalcified core needle biopsies.

BACKGROUND: Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) guide the clinical management of breast cancer metastases. Decalcification of bone core needle biopsies (CNBs) can affect IHC. In the current study, the authors sought to define whether fine-needle aspiration (FNA) would be a better alternative to CNB for reliable IHC. METHODS: Patients with breast cancer metastases to bone that were sampled by both CNB and FNA were selected. ER, PR, and HER2 were performed in FNA cell blocks (FNA-CBs) and concurrent decalcified CNBs. Discrepancies were classified as minor when there was a difference of up to 30% nuclear staining in IHC for ER and PR between paired samples and as major when a clinically relevant change was observed (ie, positive vs negative). Quantitative reverse transcriptase-polymerase chain reaction of ESR1 messenger RNA levels was performed on FNA/CNB pairs with discrepancies for ER IHC. IHC status of the primary breast carcinoma was recorded. RESULTS: Concordance rates for ER, PR, and HER2 were 89%, 67%, and 93%, respectively, between FNA-CB and CNB pairs from 27 patients. Major discrepancies were noted in approximately 11% of FNA/CNB pairs for ER IHC and in 33% of FNA/CNB pairs for PR. ESR1 messenger RNA levels of FNA/CNB matched samples were similar and did not explain the differences in ER IHC expression in the majority of cases. Two of 27 FNA/CNB pairs had different results for HER2 IHC that changed from negative on CNB to equivocal (2+) on FNA-CB. Both cases had prior HER2 amplification by fluorescence in situ hybridization. CONCLUSIONS: FNA-CB and CNB appear to constitute acceptable methods for the assessment of ER, PR, and HER2 for clinical decision making.

Low interobserver agreement in cytology grading of mucinous pancreatic neoplasms.

BACKGROUND: Identifying high-grade features in patients with pancreatic mucinous neoplasms (MNs) is important for patient management. The reproducibility of MN cytology grading has been evaluated to a limited extent. In the current study, the authors evaluated interobserver variability in grading MNs and the identification of neoplastic mucin in endoscopic ultrasound-guided fine-needle aspiration specimens. METHODS: A 54-case grading set was created from histologically confirmed MNs (44 MNs) and nonmucinous lesions with abundant gastrointestinal contamination (10 nonmucinous lesions). Six observers received a tutorial, reviewed prescreened slides, and recorded: 1) a diagnosis according to a 6-tiered system (TS) (nondiagnostic, atypical [ATP], mucinous cyst low grade [MCLG], mucinous cyst high grade, suspicious for adenocarcinoma, and positive for adenocarcinoma); 2) the cyst fluid carcinoembryonic antigen diagnosis (CEADX); and 3) the presence of neoplastic musin. Interobserver agreement (IOA) was evaluated by calculation of kappa coefficients (Kappa). Diagnostic accuracy was not evaluated. RESULTS: The IOA was lowest for the 6-TS (Kappa, 0.13; P<.001). The CEADX was available for 18 cases (33%), including 6 of 24 MCLG cases (25%). CEADX modestly improved IOA for combined tiers of the 6-TS with ATP and MCLG as separate categories. The highest IOA was noted with a 3-TS (nondiagnostic, ATP/MCLG, and mucinous cyst high grade/suspicious for adenocarcinoma/positive for adenocarcinoma [Kappa, 0.28; P<.001]) and various 4-TS (Kappa, 0.22-0.23). IOA was found to be low for neoplastic mucin (Kappa = 0.15; P<.001). CONCLUSIONS: In a study using simulated cytology practice, observers demonstrated fair IOA for grading MNs and low IOA for identifying neoplastic mucin. Knowledge of the cyst fluid CEA level was found to modestly improve the IOA for low-grade lesions.