|LETTER TO EDITOR
|Year : 2019 | Volume
| Issue : 2 | Page : 48-49
Cell block: A boon in the world of cytology!
Sonali Susmita Nayak
Department of Pathology, Homi Bhabha Cancer Hospital and Research Center, Visakhapatnam, Andhra Pradesh, India
|Date of Web Publication||18-Sep-2019|
Dr. Sonali Susmita Nayak
Department of Pathology, Homi Bhabha Cancer Hospital and Research Center, Visakhapatnam - 530 053, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nayak SS. Cell block: A boon in the world of cytology!. Oncol J India 2019;3:48-9
Pathology is infact an art! Looking at the pattern of arrangement of the cells, deciding the degree of atypia and various other morphological features, diagnosis is deciphered. This takes years of experience to master the art. Cytopathology on the other hand, requires much more experience to put in place various aspects of the jigsaw puzzle aspirated from a needle. A good cytopathologist has to be a good histopathologist first. Wondering to provide structure to the flowing cells in a liquid, our work as a pathologist would become easier. This is how cell block works wonders.
Here is a case of how cell block helped to unfold a case mystery of a 65-year-old lady who presented with ascites and abdominal distress. Radiological examination showed a pelvic mass with left ovary not identified separately, omental thickening, retroperitoneal and pelvic lymphadenopathy, and pleural effusion. A clinical diagnosis of carcinoma ovary was made, and the fluid was sent for cytology. On microscopy, instead of three-dimensional cohesive clusters typical of adenocarcinoma, the cells were more discohesive and singly dispersed. Many cells were very pleomorphic and bizarre, having prominent nucleoli and moderate amount of cytoplasm [Figure 1]. On cell block the picture was more clear with many cells having pleomorphic cleaved nucleus [Figure 2]a. Immunohistochemistry showed the pleomorphic cells to be positive for CD3, CD30, CD4, MUM1 [Figure 2]b, [Figure 2]c, [Figure 2]d and weakly expressed CD45, CD5. There was partial loss of CD7 and CD8. Other immunomarkers such as CD20, PAX5, CD15, BCL2, BCL6, cyclin D1, CD138, ALK1, EBV LMP-1, EMA, TdT, CD10, and cytokeratin (AE1/AE3) were negative. Nodal biopsy was carried out which showed similar immunohistochemistry pattern, leading to the diagnosis of ALK-negative anaplastic large cell lymphoma.
|Figure 1: Papaniculaou stained cytology smears showing singly dispersed pleomorphic cells (x400 magnification)|
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|Figure 2: (a) Cell block of ascitic fluid (x200 magnification), (b) immunohistochemistry on cell block showing tumor cells positive for CD4 (x200 magnification), (c) immunohistochemistry on cell block showing tumor cells positive for CD30 (x200 magnification), (d) immunohistochemistry on cell block showing tumor cells positive for CD3 (x200 magnification)|
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There are many more grey areas in cytology where cell block has proven as an advantage, similar to the above discussed case. One of its important contributions is in the field of carcinoma of unknown primary. A pleural or pericardial fluid or a fine-needle aspiration from an enlarged lymph node provides us adequate material similar to a biopsy sample to run immunohistochemistry and render a diagnosis. Immunostains such as TTF-1, CDX2, and PAX8 along with the combinations of CK7 and CK20 can help point out sites of primary. Many times, the effusion fluid shows the presence of degenerating mesothelial cells with peripherally placed nucleus and abundant cytoplasm, mimicking signet ring cell carcinoma. Cell block with a MOC-31 immunostain comes to rescue in differentiating them.
In fine-needle aspiration of the liver, when pleomorphic cells are seen arranged in clusters and acini, a cytologic diagnosis can only be limited to adenocarcinoma. The distinction between primary and metastasis cannot be made. Cell block here comes to the rescue. Immunostains carried out on cell block showing tumor cells positive for CK7 and negative for CK20, CDX2, and TTF-1 would suggest a cholangiocarcinoma over a metastasis. Aspirations from liver with pleomorphic cells, indistinguishable of hepatic or epithelial origin would require positive immunomarkers with HepPar-1 and Glypican-3 along with absence of staining with CK7 and CK20 to call it hepatocellular carcinoma. When cells express immunomarkers such as synaptophysin and chromogranin, neuroendocrine tumors can be suggested.
Not only in establishing a correct diagnosis on fluid cytology, cell block can be used for prognostication. Known case of carcinoma breast, who relapse with pleural effusion can be subjected to immunomarkers ER, PgR and HER2. Carcinoma stomach presenting with effusions, HER2 can be carried out on cell block to provide treatment advantage with trastuzumab.
In the cases where biopsies are difficult to target, fine-needle aspirate converted into a cell block can help solve the issue. Retroperitoneal mass aspirate converted into a cell block where tumor cells appear positive for CD99, synaptophysin, FLI-1 and negative for CD45, cytokeratin (AE1/AE3), and Desmin, can help diagnose primitive neuroectodermal tumor. Lung carcinoma with pleural effusion now do not require a lung biopsy, as cell block of the effusion can be subjected to immunohistochemistry diagnosis of adenocarcinoma along with molecular testing with epidermal growth factor receptor mutation analysis and ALK gene rearrangement studies.
There are various methods of cell block preparation such as agarose gel method, plasma thrombin method, collodion bag cell block procedure, Cellient™ automated cell block system, and HistoGel™ method,,, which can be chosen according to the individual laboratory infrastructure and workload.
Despite numerous advantages, cell blocks are only seen in few tertiary referral centers. The quantity of sample received in small laboratories seldom reach referral centers in entirety who intend to carry out further studies on it. A great advantage to such wastage of sample would be to convert it into cell blocks.
To sum up, cell block is a means of converting the cytology aspirate into a biopsy equivalent. Cell blocks should always be used as an adjunct to cytology aspirates. This not only helps us subject the sample to immunohistochemistry testing but also helpful in molecular analysis, thus proving as a blessing in the world of cytology.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]