ASSESSMENT OF CYTOLOGIC DIAGNOSIS OF CHILDHOOD  NON HODGKIN LYMPHOMA USING  IMMUNOCYTOCHEMISTRY IN OAUTHC, ILE-IFE

ADENIYI DANIEL AJIBADE

ADENIYI DANIEL AJIBADE National Postgrduate Medical College of Nigeria (NPMCN)

Abstract

Burkitt lymphoma (BL) is the commonest childhood cancer in Nigeria, and tissue
morphology has remained the standard diagnostic method. However, most clinicians in sub
Saharan
Africa still rely solely on cytology for the diagnosis of BL because it is quick and inexpensive.
Distinguishing BL from other confounding childhood tumours, using cytology remains a
challenge. This study was designed to assess the validity of cytology in the diagnosis of BL,
using immunocytochemistry as the gold standard.
This study was both prospective and retrospective. Eighty-four subjects were recruited
using a convenient sampling technique but only 50 cases had complete data; 41 prospective and
nine retrospective cases. Immunocytochemistry using BCL-2 and Ki-67 was done. Burkitt
lymphoma was diagnosed when BCL-2 was negative with Ki-67 grade of at least 90%.
Using cytology with Leishman staining, 33 (66%) were diagnosed with BL, 17 (34%)
nonBL (16 lymphoblastic lymphoma/leukaemia and 1 unclassifiable). Of the 33 diagnosed
cytologically as BL, 19 were confirmed by immunocytochemistry. The sensitivity and
specificity were 79% and 46% respectively. The positive and negative predictive values were
58% and 71% respectively. The degree of agreement between immunocytochemistry and
cytology was fair (Cohen’s Kappa score, 0.25). Due to better staining reactions in prospective
slides, a sub-analysis of the prospective cases (n = 41) yielded sensitivity and specificity of 76%
and 60% respectively, with positive and negative predictive values of 66.7% and 70.6%
respectively, and an improved Cohen’s Kappa score of 0.36.

This study concludes that cytomorphology using Leishman staining is relatively
sensitive in the diagnosis of Burkitt lymphoma but not sufficiently specific.
Immunocytochemistry staining with Ki-67 and BCL-2 can substantially improve the cytologic
diagnosis of BL. It also confirmed that archival smears are not ideal for immunochemistry.