diagnostic value of monoclonal antibody panel in cases of Hodgkin's lymphoma

ABSTRACT

The interface between Hodgkin's lymphoma [HL] and B-cell NHL has become more ambiguous in recent years. Yet, the clinical presentation, prognosis, and treatment requirement of Hodgkin's lymphoma are very different from most B-cell NHL. Thus, distinguishing between those lymphomas is still mandatory. Reviewing and immunophenotyping [using a monoclonal antibody panel] of cases diagnosed by routine histologic sections stained with hematoxylin and eosin [H and E] as Hodgkin's lymphoma, subtyping the cases in view of the new classification based on morphologic and immunophenotypic data, as well as studying the efficacy of human fascin antibody as a new marker for Reed-Sternberg cells. All cases were submitted to pathological examination of the routine H and E stained section as well as immunohistochemical evaluation of fascin, CD30, CD 15, CD20, and CD3 expression with subsequent re-evaluation of cases and establishing a final diagnosis based on morphologic and immunophenotypic data. In the present work, positive immunostaining for fascin was expressed in 97.7% of classic HL, CD30 in 80.9%, CD 15 in 70.2%, and CD20 in 10.6%. Only 26 cases [57.7%] showed coexpression of CD30 and CD15. After the review of immunohistochemical slides the diagnosis was confirmed in 37 cases of classic HL. Problematic cases were reclassified into CHL of mixed cellularity subtype [2 cases], CHL of lymphocyte rich subtype [2 cases], and CHL of the lymphocyte depletion subtype [2 cases]. Two additional cases were classified as T-cell rich large B-cell lymphoma [TCRBCL]. Two cases remained unclassified after immuno staining. The present study emphasized that immunohistochemistry supports and refines the H and E based diagnosis of Hodgkin's lymphoma and that Fascin is a sensitive marker for RS cells and may be used to differentiate between Hodgkin's and non-Hodgkin's lymphoma in difficult cases. Furthermore, complete immunohistochemical panel is needed to distinguish between T-cell rich B-cell lymphoma and lymphocyte rich-classic Hodgkin's lymphoma whether nodular or diffuse taking into consideration that absence of CD 30 or CD 15 immuno staining or expression of CD20 does not 'rule out the diagnosis of classic Hodgkin 's lymphoma and that coexpression of CD 30 and CD 15 when coupled with CDS expression necessitates complementary studies