Use of immunohistochemistry in the differential diagnosis of nasopharyngeal tumours in resource limited-settings: defining a cost-effective approach

Abstract

Background: Squamous cell carcinomas (SCC) arc the most common nasopharyngeal tumors (NP) subtypes, however other tumors particularly Non-Hodgkin's lymphomas (NHL), occur in the nasopharynx and require different treatment approach. Therefore, identifying and distinguishing these tumors from carcinomas is crucial for appropriate patient management. This study reviews the diagnostic accuracy of NP with and without the use of immunohistochemistry (IHC) and attempts to define meaningful, cost-effective immunohisto-chemical approach in low-resource setting. Materials and methods: Nasopharyngeal tumours (52 cases) identified in the database of Department of Pathology, University College Hospital, Ibadan, Nigeria in the period January 2007 to December 2012 were reviewed. The diagnosis based on haematoxylin and eosin stained sections were Nasopharyngeal carcinomas (41 cases), Poor differentiated tumour (2 cases), Non-Hodgkin's lymphomas (7 cases), Adenoid cytic carcinoma (1 case) and Small blue cell tumour (1 case). A limited IHC antibody panel consisting of Cytokeratin cocktail (AE1/AE3/ CAM5.2), CD20 and CD3 were performed on all cases and subtyping T-cell NHL using CD30 and Desmin for the small blue cell tumour typing. The previous morphologic diagnosis and post IHC diagnosis were compared to determine accuracy/ error rate. Results: Reviewed post-IHC classification of available 52 cases includes: NPC (39), NHL (11), adenoid cystic carcinoma (1) and Rhabdomyosarcoma (1), 2 cases of NHL were misclassified as carcinoma based on morphology alone.