Pleural marginal zone B-cell lymphoma presenting with pleural effusion: A case diagnosed by ancillary tests on agarose cell block sections

초록

Background: Extranodal marginal zone B-cell lymphoma (EMZBL) of mucosa-associated lymphoid tissue type occurs in a wide variety of body sites including lung. However, pleural presentation of EMZBL is not common. We present a case of this tumor diagnosed by pleural effusion cytology with ancillary tests using an agarose cell block prepared from the residue remaining after routine liquid-based smear preparation of a lymphocyte-rich pleural effusion sample. Methods: The patient was a 81-year-old woman who presented with pleural effusion. The pleural fluid received for liquid based cytology was processed for routine Pap-stained smear preparation using SurePathTM platform. The residual material remaining after SurePath smear preparation was centrifuged and the cell pellet was precessed for preparation of a formalin-fixed cell block using a modified agarose cell block technique. Sections cut from the agarose cell block was used for immunocytochemistry from CD3, CD5, CD20, CD21, CD23, CD43, Bcl6, CD10, MUM1, and Cyclin D1 and in situ hybridization for kappa and lambda immunoglobulin light chains. Results: The SurePath smear was high cellular in cellularity and disclosed many somewhtat monomorphic small lymphocytes and a small number of reactive small mesothelial cells. The agarose cell block disclosed similar cytologic features. The immunocytochemistry revealed that the luymphocytes consisted predominantly of CD20+ small B-cells that negative for CD5, CD23, CD43, Bcl6, CD10, MUM1, and Cyclin D1. Restriction for kappa indicative of monoclonality was demonstrated in a minor portion of the lymphocytes. A diagnosis of extranodal marginal zone B-cell lymphoma was rendered based on cytologic and features of the ancillary tests, which was confirmed by histology and ancillary tests of the pleural biopsy sample.