Ann E. Walts

CINtec® PLUS dual immunostain: A triage tool for cervical pap smears with atypical squamous cells of undetermined significance and low grade squamous intraepithelial lesion

ASC and LSIL comprise the majority of abnormal Pap smears. Currently, high‐risk human papillomavirus testing is utilized to triage women with ASC for colposcopy; however, no cost effective triage method is available for LSIL. p16 and Ki‐67 have each been shown to be good biomarkers for high grade cervical intraepithelial neoplasia (HG CIN).We evaluated the role of the CINtec® PLUS p16/Ki‐67 dual immunostain as a marker for underlying (U) or subsequent (S) HG CIN. One hundred and eighty eight cervical SurePath Pap smears with histological and/or cytological follow‐up were retrieved from our departmental files. The Pap stained slides were destained and then immunostained utilizing the CINtec® PLUS dual staining reagent kit. Results of the dual stain were correlated with follow‐up diagnoses. Sensitivity, specificity, and positive and negative predictive values of CINtec® PLUS for U or S HG CIN were compared with those of HR HPV testing and with p16 and Ki‐67 immunostaining alone. The sensitivity of CINtec® PLUS for U or S HG CIN was 91% in the ASC group and 100% in the LSIL group, while the corresponding specificities were 61 and 43%, respectively. The sensitivity and specificity of CINtec® PLUS for U or S HG CIN in both groups combined were 97 and 53%, respectively. CINtec® PLUS was more specific than HR HPV testing and Ki‐67 and p16 immunostains alone in detecting an U or S HG CIN. CINtec® PLUS is a helpful adjunct in identifying U or S HG CIN when applied to SurePath Pap smears with ASC or LSIL. Diagn. Cytopathol. 2013.

BAP1 Immunostain and CDKN2A (p16) FISH Analysis

Loss of BAP1 by immunohistochemistry (IHC) and CDKN2A(p16) deletion by fluorescence in situ hybridization (FISH) have been proposed to distinguish malignant mesothelioma (MM) from atypical reactive mesothelial proliferations (ARMP) in effusions but it is uncertain whether both tests are needed routinely.

Follicular lesion of undetermined significance in thyroid FNA revisited

Controversy exists regarding the validity of follicular lesion of undetermined significance (FLUS), an indeterminate diagnostic category of The Bethesda System for Reporting Thyroid Cytopathology (BSRTC). According to BSRTC, FLUS carries a 5–15% risk of cancer. This study was designed to determine if cytomorphology could stratify FLUS into subgroups with different risks of malignancy. Reports of 127 consecutive FNAs reported as FLUS with subsequent tissue diagnoses were evaluated for the presence of various cytologic features and the results were correlated with histological diagnoses. FLUS cases with focal nuclear atypia (nuclear overlap/crowding, nuclear grooves/membrane irregularities, nuclear enlargement, and/or nuclear pseudoinclusions) were more frequently malignant on excision whereas those with architectural atypia (microfollicles) were more often benign on excision (P < 0.05). The presence of any one or more of these nuclear features increased the risk of carcinoma in subsequent thyroid resection. Papillary carcinomas predominated in excised FLUS cases with focal nuclear atypia whereas most FLUS with architectural atypia were adenomas or hyperplastic nodules on histological evaluation. BSRTC recommends that thyroid aspirates containing follicular cell nuclear and/or architectural atypia insufficient for a diagnosis of suspicious for follicular neoplasm, suspicious for malignancy or malignant be classified as FLUS. Our findings indicate that FLUS cases with focal nuclear atypia carry a risk for malignancy that is substantially higher than that assigned to FLUS and are best classified as suspicious. FLUS cases lacking these atypical nuclear features have a risk for malignancy that approximates the risk BSRTC has assigned to FLUS. Diagn. Cytopathol. 2014;42:18–22.

Cytologic Differential Diagnosis of Malignant Mesothelioma and Reactive Mesothelial Cells With FISH Analysis of p16

Mesothelioma patients often present with serosal effusions, which are ideal for cytopathological diagnoses. However, the morphological overlap between malignant and benign mesothelial proliferation can make a conclusive cytological diagnosis of mesothelioma elusive because immunohistochemical staining does not discriminate definitively between the two in this setting. p16 is deleted in up to 80% of pleural mesotheliomas. The aim of this study was to establish the correlation between the p16 deletion status of the cell block with that of its corresponding tumor using fluorescence in situ hybridization (FISH) analysis for individual patient tumors.

Optimization of the peritoneal lavage

Review of 275 consecutive peritoneal lavages and concurrent histologic material from gynecologic operations suggested that cytologic evaluation was clinically indicated for only 60.7% of the lavages, representing 46% of the patients in the study. More than one concurrent lavage was received from 21.6% of all patients in the study, comprising 50% of patients with malignant lavages, 18.7% of patients with benign lavages, and 5.3% of patients for whom cytologic evaluation of peritoneal lavage was not clinically indicated. Malignant cells were diagnosed in 15% of the 167 lavages for which cytologic examination was clinically indicated. In this series of patients, identification of malignant cells in peritoneal lavages did not increase the tumor stage beyond that obtained solely from examination of the concurrent histologic material. There were no false‐positive cytologic diagnoses and no lavages in which neoplastic cells were misinterpreted as benign. A significant number of lavages, including several from patients with histologically confirmed peritoneal tumor, were sparsely cellular and/or excessively bloody. It is suggested that although peritoneal lavages might be collected during all gynecologic operations, only specimens from selected cases should be submitted for cytologic evaluation, and greater attention should be given to specimen collection to ensure that only well‐preserved and representative material from the peritoneum is submitted for cytologic evaluation. Diagn. Cytopathol. 1998;18:265–269.

Low cost-effectiveness of CD3/CD20 immunostains for initial triage of lymphoid-rich effusions: An evidence-based review of the utility of these stains in selecting cases for full hematopathologic workup†

CD3/CD20 immunostains are often performed in the initial cytological evaluation of lymphoid‐rich pleural effusions (LR‐PE). Most benign LR‐PE are predominantly composed of T(CD3+) cells while most malignant LR‐PE are of B(CD20+) cell lineage. As part of the effort to contain laboratory costs and improve diagnostic accuracy, there is increasing interest in applying principles of evidence‐based pathology to the use of immunostains. In this retrospective study, we reviewed the effectiveness of CD3/CD20 immunostains as a diagnostic or triage tool during the initial evaluation of 258 consecutive LR‐PE. 196 (76%) of the LR‐PE were ultimately diagnosed as reactive lymphocytosis and 62 (24%) as lymphoma/leukemia (L/L). There was a previous diagnosis of L/L, concurrent diagnostic tissue, and/or clinical evidence of L/L in 44 (71%) of the L/L effusions. An initial diagnosis of L/L was made in the remaining 18 (29%) cases. Sixteen of these 18 cases showed large cells with high‐grade features that mandated L/L workup. In only 2 (0.8%) of the 258 LR‐PE, CD3/CD20 stains were helpful to identify small cell lymphocytic lymphoma (SLL) in patients without concurrent peripheral lymphocytosis. CD3/CD20 immunostains do not appear to provide a cost‐effective method to diagnose or triage the vast majority of LR‐PE submitted to a clinical cytology laboratory. An algorithm that considers history, blood counts, and cytomorphology allows for cost‐effective selection of LR‐PE that warrant comprehensive hematopathologic workup. Our findings underscore the feasibility of applying evidence‐based principles to develop guidelines for the cost‐effective utilization of immunostains in cytology. Diagn. Cytopathol. 2012.

Fine-needle aspiration of extranodal Hodgkin's lymphoma misinterpreted as carcinoma.

Dear Dr. Bedrossian: A 36-year-old woman was referred to our hospital after ‘‘poorly differentiated adenocarcinoma’’ had been reported in aspirate smears from the ‘‘left breast’’ and ‘‘left axilla’’ at another facility. A breast biopsy was performed and no lesions were identified on macroscopic examination of the excised tissue by the pathologist in the operating room. Therefore, a second specimen designated ‘‘deep biopsy’’ was excised. The ‘‘deep biopsy’’ consisted of a mass of rubbery tan tissue in continuity with a portion of striated muscle. Microscopic examination of the superficial biopsy showed benign breast tissue with mild fibrocystic changes. Microscopic examination of the deep biopsy was diagnostic of Hodgkin’s lymphoma (HL) and suggestive of nodular sclerosing type with numerous lacunar-type and ReedSternberg (RS) cells, lymphocytes, and eosinophils involving the chest wall (Fig. 1). No breast parenchyma was present. Immunostains including CD15 (Leu M1), CD45 (LCA), LN1, keratin AE 1/3, and EMA were consistent with HL. Given the clinical presentation as a ‘‘breast mass’’ and ‘‘axillary mass’’ in a woman without significant medical history, it is not surprising that the clinician and in turn the cytopathologist presumed the aspirates were from a breast tumor and an axillary node with metastatic tumor. Smears from both sites showed similar findings. Review of the smears (Fig. 2) illustrates how the cytological findings contributed to the misinterpretation: (a) the smears were sparsely cellular (presumably the location of the lesion deep to the breast and the sclerosis resulted in limited sampling); (b) the large bare atypical nuclei with nucleoli and a few markedly atypical epithelioid cells Fig. 1. Chest wall biopsy showing Hodgkin’s lymphoma with ReedSternberg cells and lacunar cells in a background of lymphocytes and eosinophils (H&E, 3400). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

High-grade neuroendocrine carcinoma presenting as an abscess: Diagnosis by fine needle aspiration and review of the literature

Neuroendocrine carcinomas (NEC) comprise about 2% of all carcinomas. Review of the literature indicates only a few cases of NEC presenting as an abscess, all having been diagnosed by tissue biopsy. Here, we report the FNA diagnosis of a high‐grade neuroendocrine carcinoma presenting as an abscess of the axilla/chest wall in a 68‐year‐old man and review the pertinent literature. Diagn. Cytopathol. 2008;36:670–673.