Introduction
Liver transplantation is the most effective treatment for end-stage
liver disease in children. Due to the use of immunosuppressants,
infection by the Epstein–Barr virus (EBV) is common after pediatric
liver transplantation (pLT)(1), and post-transplant lymphoproliferative
disease (PTLD) related to EBV is a serious complication with a poor
prognosis that can lead to death after pLT(2, 3).
Compared to adults, children with PTLD show obvious characteristics in
terms of incidence rate and performance. The incidence of PTLD after
solid organ transplantation in children is higher than that in
adults(4). With the growing number of pLT procedures in recent years,
the number of pediatric cases of EBV-related PTLD has also increased
year by year. Different from the 80%–90% rate of EBV infection in
adults, only about 20%–50% of children are EBV carriers by the age of
5 years, and their symptoms may be hidden or they may show symptoms of
EBV infection (fever, night sweats, and weight loss), lymph node
hyperplasia, or graft dysfunction(5-8).
Histopathological examination is the gold standard for the diagnosis and
classification of PTLD after pLT. According to the World Health
Organization classification of lymphomas (2017) revised edition, PTLD
can be divided into the following categories: (I) non-destructive PTLD,
including plasmacytic hyperplasia PTLD, infectious mononucleosis PTLD,
and florid follicular hyperplasia PTLD; (II) polymorphic PTLD; (III)
monomorphic PTLD, including B- and T-/natural killer cell types; and
(IV) classical Hodgkin’s lymphoma PTLD(9-11). However, as an invasive
assessment, histopathological examination will inevitably do some harm
to patients. As a non-invasive method,18F-fluoro-2-deoxy-D-glucose
(18F-FDG) positron emission tomography (PET)/computed
tomography (CT) imaging has been widely used in adult PTLD, but its
application in children is less commonly reported. A recent study
involving 28 children with PTLD showed that 18F-FDG
PET/CT has a good positive predictive value (PPV) and specificity, but
its sensitivity and negative predictive value (NPV) were poor. This may
be because children grow and develop rapidly, and there are high
metabolic regions such as the brain, kidneys, and heart that render18F-FDG PET/CT unable to detect PTLD that can be
confirmed by histology in these regions(12). Studies have shown that the
median peak standardized uptake value (SUVpeak) at the biopsy site of
monomorphic PTLD is significantly higher than those of the polymorphic
and non-destructive subtypes of PTLD. However, it is difficult to
distinguish between PTLD-negative cases and non-destructive PTLD cases
using SUVpeak due to the significant SUV overlap of the different
subtypes(13). Therefore, it is of significant interest to find an index
that can distinguish PTLD-negative cases and non-destructive PTLD cases
with high sensitivity, specificity, PPV, NPV, and accuracy; confirm or
refute the clinical suspicion of PTLD; and identify suggestive lesions
accessible for biopsy. This study reviewed and collected clinical and
pathological data of pLT patients who underwent18F-FDG PET/CT and lymph node biopsy, explored the
indicators that can effectively distinguish PTLD-negative cases and
non-destructive PTLD cases, and evaluated their effects.