Histomorphologic and Immunophenotypic Profile of Marginal Zone Lymphoma

Marginal zone lymphoma (MZL) is a type of indolent neoplasm, arising from B-cells in marginal zones of lymph nodes and extranodal tissues. Here, we studied the histomorphologic and immunophenotypic profile of MZL. Material and Methods: Samples were obtained from the immunohistochemistry (IHC) archive of the Department of Anatomical Pathology in FMUI/CMH. The samples were cases diagnosed as MZL or mucosa-associated lymphoid tissue (MALT) lymphoma, during 2013 to 2016. Demographic profile, Hematoxylin-Eosin, and immunohistochemistry slides were analyzed. Thirty-three cases of MZL were included. Median age of all cases was 56 year-old, with male patients outnumbering females by 54.5%. Extranodal tumours made up 78.8% (26 out of 33) cases, among these 21 cases (80.8%) were in the eye. Around 18.2% (6 of 33) of MZL cases had large-cell transformation areas. There were 72.8% (24 of 33) cases showed predominantly diffuse patterns, with neoplastic cells in the form of small lymphocytes, centrocyte-like, monocytoid, and plasmacytoid cells. Lymphoepithelial lesions, large cells, and epithelioid histiocytes were found in 30.8% (8 of 26) cases; 18.2% (6 of 33) cases and 21.2% (7 of 33) cases, respectively. Vascular hyalinization was seen in 30.3% (10 of 33) cases. IHC results showed positive CD20 and negative CD3 in all cases. Cyclin D1 was negative in all available (25 of 25) cases. Low Ki-67 level (between 0–20%), was found in 72.7% (24 of 33) cases. These results showed similarities and differences with currently available literature. Further research is required to explain the existing discrepancies. Regardless of tumour location, complete IHC panel is necessary for MZL cases, as well as translocation and clonality examination.