Aberrant expression of immunohistochemistry markers in non-Hodgkin lymphoma

Introduction: The world health organization (WHO) recognizes two major categories of lymphoid neoplasms: non-Hodgkin lymphoma and Hodgkin lymphoma. Non-Hodgkin lymphoma accounts for approximately 55,000 to 60,000 new cases and approximately 19,000 deaths per year and is the fifth most common type of cancer in the United States. We evaluated the expression of immunohistochemistry markers in non-Hodgkin lymphoma to find aberrant expression of markers.Materials and Methods: In this retrospective descriptive study, 166 pathologic reports of non-Hodgkin lymphoma specimens sent to pathology department of Urmia Imam Khomeini Hospital between March 2010 until March 2016 were included. Thirty one cases were excluded from study due to incomplete information.Results: Among 135 non-Hodgkin lymphomas, 79 (58.52%) were male and 56 (41.48%) were female. The age range was between 11-93 years old (52 ± 21.34 years). Subtypes of non-Hodgkin lymphoma included Diffuse large B cell lymphoma (DLBL) (74.82%), Nodal marginal zone lymphoma (NMZL) (3.7%), Lymphoblastic T-Cell Lymphoma (3.7%), Mantle cell lymphoma (MCL) (4.44%), Angioimmunoblastic T-Cell Lymphoma (2.96%), small lymphocytic lymphoma (SLL) (2.23%), Mature B-Cell lymphoma (% 2.23), NK cell/ T-Cell lymphoma (1.48%), FL (1.48%) Anaplastic Large T-Cell (1.48%), Burkitt lymphoma (0.74%) and Adult T-Cell leukemia/lymphoma (0.74%). DLBL was the most common subtype, and aberrant expression of CD5 and CD3 markers were seen in 14.28% and 5.55%, of DLBL. Aberrant expression of CD5 in 40% of NMZL, and CD3 in 25% of MCL were also present.Conclusion: Diagnosis of different subtypes of non-Hodgkin lymphoma is based on light microscopic morphological findings and use of immunohistochemistry staining for expression of different markers. Aberrant expression of some markers can cause diagnostic difficulties. In this study several expression of markers in non-Hodgkin lymphomas were evaluated to help resolve diagnostic problems.