Howard H. Wu

Subclassification of “atypia of undetermined significance” in thyroid fine‐needle aspirates

To identify the subtypes of atypia of undetermined significance (AUS) that confers a different magnitude for the risk of malignancy (RM), thyroid fine‐needle aspiration (FNA) cases carrying a diagnosis of “atypical follicular cells” or “follicular lesion” with surgical pathology followup were included in this study. The direct smears of the aspirates were rereviewed and subclassified into four subgroups based on cytomorphology: AUS cannot exclude follicular neoplasm (AUS‐FN), AUS cannot exclude Hürthle cell neoplasm (AUS‐HCN), AUS cannot exclude papillary carcinoma (AUS‐PTC) and AUS, not otherwise specified (AUS‐NOS). Based on the followup histopathologic findings, RM not including papillary microcarcinoma (PMC), RM including PMC and the risk of neoplasm (RN) were calculated for each of the four AUS subgroups. A total of 138 AUS cases were subclassified into AUS‐NOS (48), AUS‐PTC (41), AUS‐FN (32), and AUS‐HCN (17). RM not including PMC was 32% for AUS‐PTC (P < 0.001), 25% for AUS‐FN, 8% for AUS‐NOS, 0% for AUS‐HCN, and 18% for all AUS cases. RM including PMC was 54% for AUS‐PTC (P < 0.001), 34% for AUS‐FN, 19% for AUS‐NOS, 18% for AUS‐HCN, and 33% for all AUS cases. RN was 63% for AUS‐PTC (P = 0.05), 81% for AUS‐FN (P < 0.01), AUS‐HCN 53%, AUS‐NOS 44% and 59% for all cases. In our study, subclassification enabled us to further divide AUS cases into high‐ and low‐risk groups. The high‐risk group includes AUS‐PTC with a significantly higher risk of malignancy and AUS‐FN with a significantly higher risks of neoplasm. AUS‐HCN and AUS‐NOS subgroups demonstrate a lower risk of malignancy of <10%. Diagn. Cytopathol. 2014;42:23–29.

ER, PR, and Her2 immunocytochemistry on cell‐transferred cytologic smears of primary and metastatic breast carcinomas: A Comparison Study With Formalin‐Fixed Cell Blocks and Surgical Biopsies

The use of formalin‐fixed cell blocks (CBs) for detection of ER, PR, and Her2 status of primary and metastatic breast carcinomas sampled by fine‐needle aspiration (FNA) has been extensively used in clinical practice; however, CBs sometimes lack adequate cellularity even when direct smears are cellular. The aim of this study is to assess the reliability of ER, PR, and Her2 status as demonstrated by immunocytochemical staining (ICC) on alcohol‐fixed direct smears using the cell transfer (CT) technique. FNA cases diagnosed as primary or metastatic breast carcinoma in which the status of ER, PR, and Her2 had been determined either on CB or concurrent biopsy were identified over a period of 18 months. ICC for ER, PR, and Her2 was performed on alcohol‐fixed direct smears using the CT technique. Results were compared with those reported for the corresponding formalin‐fixed tissue. A total of 47 FNA specimens from 46 patients were included in this study. ICC results were excluded from analysis if the CT smear contained fewer than 50 cells. Correlation between the ICC performed on the CT smears and the corresponding CB or biopsy revealed a sensitivity rate for ER, PR, and Her2 of 95%, 90%, and 88%, respectively with a specificity of 100% for all three markers. ICC performed on the FNA smears using the CT technique is a reliable method for assessment of the ER, PR, and Her2 status of breast carcinomas, especially when the direct smears are highly cellular and the CB lacks adequate cellularity. Diagn. Cytopathol. 2013.

EUS‐guided FNA cytology of pancreatic neuroendocrine tumour (PanNET): a retrospective study of 132 cases over an 18‐year period in a single institution

To determine the diagnostic accuracy and pitfalls of endoscopic ultrasound (EUS)‐guided fine needle aspiration (FNA) cytology of pancreatic neuroendocrine tumour (PanNET).

Utilization of cell-transferred cytologic smears in detection of EGFR and KRAS mutation on adenocarcinoma of lung

Cell-transfer technique has been proven useful for performing immunocytochemistry on fine-needle aspiration smears. However, its utility for EGFR and KRAS molecular testing has not been validated. Molecular testing was performed using the cell-transfer technique on both Papanicolaou-stained ethanol-fixed and Hema 3-stained air-dried smears from 32 fine-needle aspiration samples that had diagnoses of adenocarcinoma of the lung, and then was compared to the results of the corresponding formalin-fixed paraffin-embedded tissues. The molecular testing was successfully performed on 32 of 32 ethanol-fixed and 31 of 32 air-dried samples. The molecular results on ethanol-fixed and air-dried smears showed 100% agreement. There is 100% (32/32) agreement for the EGFR and 97% (31/32) agreement for the KRAS between the cell-transfer technique and formalin-fixed paraffin-embedded tissues. One discrepant case was due to low percentage of tumor cells on the smears. Cell-transfer technique is a reliable alternative method for EGFR and KRAS testing if the cell blocks lack adequate cellularity.

Immunocytochemistry performed on the cell-transferred direct smears of the fine-needle aspirates: a comparison study with the corresponding formalin-fixed paraffin-embedded tissue.

Immunocytochemistry (ICC) performed on the cell-transferred cytologic smears (CTCS) of fine-needle aspiration (FNA) is useful when the cell blocks lack adequate material. The comparison of the ICC results from the CTCS of FNA with the corresponding formalin-fixed paraffin-embedded tissue (FFPE) has not been reported previously. We applied 12 commonly used ICC antibodies on 160 pieces of ethanol-fixed, cell-transferred Papanicolaou-stained smears obtained from 42 FNA specimens and compared the staining results with the corresponding FFPE on which the same panel of immunostains was performed. Of the 160 pieces of transferred materials, only 3 (1.9%) were lost during specimen processing. In total, 153 of 157 (97.5%) showed staining results that agreed with the corresponding FFPE, including 78 of 81 positive staining and 75 of 76 negative staining cases. ICC performed on the cell-transferred FNA smears is reliable and shows staining results highly comparable with the corresponding FFPE tissue.

The utility of fine-needle aspiration in the diagnosis of primary and metastatic tumors to the lung: a retrospective examination of 1,032 cases.

Background: With the emergence of improved treatment strategies for patients with malignant lung tumors, it has become increasingly important to adequately diagnose and subclassify lung lesions. In our large retrospective study, we assessed the utility of fine-needle aspiration (FNA) in the diagnosis of primary and metastatic tumors to the lung. Methods: A computerized search of our laboratory informatics system was performed to identify cases from FNA of the lung and FNA of metastatic lung cancers to other sites. All of the corresponding surgical pathology reports were also reviewed. All of the cases were categorized as atypical (A), benign (B), malignant (M), nondiagnostic (ND), or suspicious (S) for data analysis purposes. Results: A total of 1,032 FNA cases were categorized as follows: 34 (3.3%) A, 142 (13.8%) B, 717 (69.5%) M, 121 (11.7%) ND, and 18 (1.7%) S. Of the 717 cases of malignant FNA, a specific tumor type was able to be rendered on cytomorphology alone or with the help of immunostains in 99% as follows: adenocarcinoma (296 cases, 41%), squamous cell carcinoma (158 cases, 22%), metastatic tumors (123 cases, 17%), small cell carcinoma (56 cases, 8%), non-small cell lung carcinoma (NSCLC) (58 cases, 8%), neuroendocrine carcinoma (15 cases, 2%), and poorly differentiated carcinoma (4 cases, 1%). Out of all NSCLC cases, 89% were able to be subclassified as either adenocarcinoma or squamous carcinoma. The most frequent origins of metastatic tumors to the lung were renal cell carcinoma (n = 22), melanoma (n = 17), colon (n = 15), breast (n = 14), and urothelial carcinoma (n = 10). There was also metastasis from 18 other organs with fewer than 5 cases each. There were 333 correlated histologic specimens including 191 small biopsies and 142 resection specimens. Diagnostic sensitivity and specificity for malignancy were 96 and 100%, respectively. Diagnostic accuracy was 97%. Sampling error resulted in 8 false-negative cases on FNA. Conclusions: FNA is both sensitive and specific in the diagnosis and subclassification of both primary and metastatic lung tumors. Eighty-nine percent of NSCLC cases were able to be further subclassified as adenocarcinoma or squamous cell carcinoma by FNA.

Percutaneous biopsy of the renal mass: FNA or core needle biopsy?

In recent years, there have been increasing indications for percutaneous renal biopsy. Fine‐needle aspiration (FNA), with or without core needle biopsy (CB), has been used increasingly in the management of renal tumors at the study institution.

Pancreatic fine‐needle aspiration cytology in patients < 35‐years of age: A retrospective review of 174 cases spanning a 17‐year period

Pancreatic lesions in young patients are relatively rare and, to our knowledge, the clinical value of pancreatic fine needle aspiration (FNA) in patients < 35 years of age has not been previously established by any other large retrospective studies. All pancreatic endoscopic ultrasound‐guided FNA (EUS‐FNA) cases performed on patients < 35 years of age were identified for a 17‐year period (1994–2010). All FNAs and all available correlating surgical pathology reports were reviewed. There were a total of 174 cases of pancreatic FNA performed on 109 females and 65 males under the age of 35 (range: 8–34, mean: 27 years). The FNA diagnoses included 37 malignant, 114 negative, nine atypia/suspicious, and 14 cases that were nondiagnostic. Of the 37 malignant FNA cases, the diagnoses included 18 pancreatic neuroendocrine tumors (PanNeT), 11 solid pseudopapillary neoplasms (SPN), five adenocarcinomas and three metastatic neoplasms. Histologic follow‐up was available in 22 of the 37 malignant cases diagnosed by FNA, and the diagnosis was confirmed in 21 cases. One pancreatoblastoma was misclassified as SPN on EUS‐FNA. False negative diagnoses were noted in three cases of low‐grade mucinous cystic neoplasm and one case of PanNeT. The most common type of neoplasms diagnosed by EUS‐FNA in patients < 35‐year old is PanNeT, followed by SPN with both tumors accounting for 75% of all the neoplasms encountered in this age group. The sensitivity and specificity for positive cytology in EUS‐FNA of the pancreas to identify malignancy and mucinous neoplasms were 90% and 100%, respectively. Diagn. Cytopathol. 2014;42:297–301.

The usefulness of the cell transfer technique for immunocytochemistry of fine-needle aspirates.

The use of immunocytochemistry as an important ancillary technique for the workup of fine‐needle aspiration (FNA) specimens is an important component in the daily practice of cytopathology. Although cell block preparations are commonly used, immunocytochemistry cannot be completed if the cell blocks are hypocellular. As an alternative approach when conventional cell blocks fail, immunocytochemistry can be performed on cell‐transferred direct smears. Multiple immunostains can be applied to a single direct smear using the cell transfer technique (CTT).

Detection of BRAF Mutations on Direct Smears of Thyroid Fine-Needle Aspirates Through Cell Transfer Technique

OBJECTIVES To determine the utility of the cell transfer technique (CTT) for BRAF molecular testing on thyroid fine-needle aspiration (FNA) specimens. METHODS Polymerase chain reaction (PCR)-based BRAF molecular testing was performed on tissues obtained through CTT from both air-dried and ethanol-fixed direct smears of thyroid FNA specimens and then compared with the corresponding thyroidectomy formalin-fixed, paraffin-embedded (FFPE) tissues on 30 cases. RESULTS BRAF testing was successfully performed on 29 of 30 air-dried CTT, 27 of 30 ethanol-fixed CTT, and 27 of 30 FFPE tissues. The results exhibited 11, 13, and 13 BRAF mutations and 18, 14, and 14 wild types for the air-dried CTT, the ethanol-fixed CTT, and the FFPE tissues, respectively. The concordance rate was 96% between air-dried and ethanol-fixed CTT tissues, 88% between air-dried CTT and FFPE tissues, and 92% between ethanol-fixed CTT and FFPE tissues. CONCLUSIONS PCR-based BRAF mutational testing can be reliably performed on the direct smears of the thyroid FNA specimens through the application of CTT.