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.