Tissue Microarray from Cell Block Material (cbTMA)—An Additional Shot for Cytology in the Predictive Pathology Era: The PD-L1 Experience

Generally, predictive biomarker tests are clinically validated on histological formalin-fixed, paraffin-embedded (FFPE) samples. In addition to FFPE samples, cytological samples have also emerged as a useful approach to detect predictive biomarkers. However, as of today, despite the promising results reported in the recent literature, their full implementation in routine clinical practice is still lagging owing to a lack of standardized preparatory protocols, challenging assessments of cyto-histological correlation, and variable inter-observer agreement. The aim of this report was to explore the possibility of implementing a large-scale validation of predictive biomarker testing on cytological material. To this aim, we evaluated the technical feasibility of PD-L1 assessment on a cell block (CB)-derived tissue microarray (cbTMA). Consecutive and unselected CBs prepared from metastatic lymph node fine-needle cytology (FNC) samples were retrospectively collected and used for TMA construction. PD-L1 immunohistochemistry (IHC) was carried out on cbTMA sections with the companion diagnostic kit SP263 assay. TMA contained 33 CB-derived cores. A total of 20 sections were hematoxylin and eosin (H&E) stained. Overall, 29 (88%) samples were visible at least in one H&E-stained slide. Four cases out of five sections stained with the SP263 assay (4/29, 13.8%) showed PD-L1 positivity in neoplastic and/or immune cells; remarkably, no unspecific background was observed. Although our study was based on a limited and non-selected series, our findings do provide proof of concept for the use of cbTMA in predictive biomarker testing on cytological material in large-scale post-clinical trial validation studies, multicenter studies, and quality control programs.

Potential application of cryobiopsy for histo-molecular characterization of mediastinal lymph nodes in patients with thoracic malignancies: a case presentation series and implications for future developments

Background The management of non-small cell lung cancer (NSCLC) has become increasingly complex due to the evolution of personalized medicine approaches. Such approaches are characterized by the necessity of adequate tumor samples; hence, improved biopsy techniques are needed. Transbronchial lung cryobiopsy is a novel endoscopic procedure designed to collect peripheral pulmonary tissue, and it is currently employed in interstitial lung diseases. The use of this technique in oncology might result in improved mediastinum staging and molecular characterizations; however, available data involving the use of a cryoprobe on mediastinal lymph nodes are still limited. Case presentation Here we present a series of five consecutive patients who underwent endoscopic assessment of mediastinal lymph nodes for oncologic reasons. All patients were subjected both to endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) and cryobiopsy of mediastinal lymph nodes during the same procedure, and no complications were observed. In three of the reported cases, both cryobiopsy and cell block from EBUS TBNA were positive, while in one case cryobiopsy was not diagnostic and EBUS TBNA was negative; moreover, one case showed discordance between the procedures, as cryobiopsy was negative and cell block obtained from multiple stations was diagnostic for small cell lung cancer. In one case involving a patient treated for lymphoma, cryobiopsy provided more complete histologic characterization, and in another case involving a patient affected by NSCLC cryobiopsy provided more material for molecular analyses. Conclusion This case presentation series suggests that cryobiopsy, which has been generally used on peripheral lung lesions so far, is a feasible and safe approach for diagnosis and staging of mediastinal lymph nodal involvement, especially when station 7 is involved. Compared to EBUS TBNA, cryobiopsy might provide more adequate histological samples, with a possible impact on molecular characterizations and, therefore, therapeutic decisions. However, the learning curve of the procedure has not to be understated and optimal protocols for implementing this technique are needed. In our opinion, further studies designed to integrate the routine use of cryobiopsy in current practice for solid and eventually hematologic tumors with mediastinal lymph node involvement are warranted.

FNA Cytological Diagnosis of Breast Metastasis From a Plantar Melanoma: Case Report

BackgroundBenign and primary malignant breast tumors are quite common, but metastatic malignancies are rare and the diagnosis is challenging due to its low incidence.Case presentationHere, we report a case of metastatic melanoma which was initially diagnosed in breast by fine needle aspiration(FNA). Although the suggestive diagnosis is based on the strong pigmentation of tumor cells in FNA smears, cell block and immunohistochemical melanocyte markers (HMB45 and MART-1) help to confirm the diagnosis. Later, FNAs from lower limb mass and inguinal mass also revealed the same tumor. In addition, a pigmented nevus with the appearance of malignant melanoma was found on the sole of the patient's right foot.Conclusion Our report illustrates the morphological evaluation on cytology，ancillary testing on cell block and meticulous clinical examination play a pivotal role in establishing the correct diagnosis.

EMA-AND USEFUL IMMUNOCYTOCHEMICAL MARKER AT DIFFERENTIATION OF GLANDULAR MALIGNANT CELLS FROM ATYPICAL MESOTHELIAL CELLS ON CELL BLOCK PREPARATION OF BODY EFFUSIONS

The detection of the malignant cells by cytologic method has long been practised. The detected malignant cells are difficult to be typed specially in the situations of overlapping cytomorphology. The conventional cytologic preparation may harbour lower number of malignant cells but the method of cell block offers high detection rates of such malignant cells. Still the problem remains when the evaluation is short by morphological features and requires immunoexpression studies. The commonest situation encountered of overlap cytomorphology is the distinction between well differentiated adenocarcinoma from reactive mesothelial cells with atypia in effusion. Such a distinction is not only important for the purposes of diagnosis but also for prognostification by stage and management of the patient .The review presents the experiences of the past studies over utility of EMA in detection and segregation of the cells of well differentiated adenocarcinoma infiltrating the effusions from reactive atypical mesothelial cells. The present review is compiled from the publications from various institute across the globe and shares the authors experience for the utility of epithelial membrane antigen over the cell block of effusions at distinction of overlap cytomorphology. Compilation of the study by inclusion of articles by 1,2,3,3,4,5,6,7,8,9,10.The articles were searched through google engine and Pubmed search. The 10 articles dealing onto the role of EMA as a immunocytochemical marker have affirmed the high sensitivity and specificity of EMA at seggregating glandular malignant cells from atypical mesothelial cells on cell block preparation of body effusions.The range of sensitivity and specificity for EMA was found to be 81% -100% and 98.86 -100% respectively.The positive predictive value range from 92-97% and negative predictive value ranging from 88.64 – 100%. All the studies reviewed confirmed the high value of significance (P value for EMA). The systematic review carried out re-affirms the role of EMA in the situations of of indistinguishable cytomorphology of adenocarcinoma from that of benign , reactive , atypical mesothelial cells. The overall diagnostic utility of EMA was conducted to br over 90% in such situations.