Discussion
This is the first case report describing a primary pancreatic
fusion-positive RMS. The treatment of our patient lead to severe side
effects that considerably affected the patient’s health and quality of
life.
In retrospect, while a diagnosis of SPN was strongly suspected, we
wonder if obtaining a biopsy to confirm the diagnosis at presentation
could have changed our treatment approach and decreased morbidity.
Limited evidence can be found regarding initial diagnostic approaches
for pediatric pancreatic tumors. An Italian national cooperative
initiative created diagnostic and therapeutic recommendations for
malignant pancreatic lesions in children. These guidelines state that
primary excision should be attempted if complete and non-mutilating
resection is feasible. If not, a biopsy should be attempted to direct
chemotherapy, hoping for tumor shrinkage prior to subsequent resection,
including PD15. Recently, Law et al. showed that
combining imaging (CT and/or endoscopic ultrasound [EUS]) with an
EUS-fine needle biopsy (EUS-FNA) increased the diagnostic yield for SPN
to 82% from 24% for CT alone16, while another study
showed a diagnostic yield of 100% with FNA for SPN when using the
appropriate molecular markers17. Increased accuracy in
determination of the malignant nature of pancreatic cyst was also
achieved when using EUS-FNA compared to CT or
MRI alone18. Interestingly, although pancreatic
biopsies can lead to adverse events, the percentage of events with
EUS-FNA is only 0 to 5%19. Taken together, these data
support obtaining a biopsy by EUS-FNA or other minimally invasive
methods during the initial evaluation of a pancreatic mass, especially
when primary excision would involve potentially significant anatomical
and functional perturbations.
Local control for intermediate-risk RMS can be achieved through surgery,
radiotherapy or both. Although local failure in alveolar RMS is higher
in group III tumors (19%), historically treated with radiation therapy
alone, vs. group II tumors (10%), in which surgery and radiation
therapy were used, the 5-year even free survival (EFS) between the two
groups is similar20. Delayed primary excision (DPE)
with reduced doses of radiation has yielded results similar to
radiation alone21. Considering the expected morbidity
associated with PD, but despite our impression that our patient had an
SPN, a biopsy at the time of presentation of our patient could have led
to reconsideration of surgery, potentially decreasing her long-term
complications.
This case report illustrates the limitation of imaging for determination
of the nature of a pancreatic mass. The evidence regarding long-term
tumor outcomes of pediatric and adolescent patients undergoing PD for
benign or malignant tumors is limited, but show similar deficits in
endocrine and exocrine pancreatic function and gastrointestinal
morbidity when compared to adults2,3,5,22,23. We argue
that a biopsy should be obtained at initial presentation of a pancreatic
mass, especially if primary excision involves a procedure with risk of
significant morbidity. There is a need as well to better understand the
long-term outcomes of PD in the context of pediatric benign and
malignant tumors.