Peripancreatic paraganglioma: Lesson from a round table

Abstract

We described the case of a peripancreatic paraganglioma (PGL) misdiagnosed as pancreatic lesion. Surgical exploration revealed an unremarkable pancreas and a large well-defined cystic mass originating at the mesocolon root. Radical enucleation of the mass was performed, preserving the pancreatic tail. Histologically, a diagnosis of PGL was rendered. Interestingly, two previously unreported mutations, one affecting the KDR gene in exon 7 and another on the JAK3 gene in exon 4 were detected. Both mutations are known to be pathogenetic. Imaging and cytologic findings were blindly reviewed by an expert panel of clinicians, radiologists, and pathologists to identify possible causes of the misdiagnosis. The major issue was lack of evidence of a cleavage plane from the pancreas at imaging, which prompted radiologists to establish an intra-parenchymal origin. The blinded revision shifted the diagnosis towards an extra-pancreatic lesion, as the pancreatic parenchyma showed no structural alterations and no dislocation of the Wirsung duct. Ex post, the identified biases were the emergency setting of the radiologic examination and the very thin mesocolon sheet, which hindered clear definition of the lesion borders. Original endoscopic ultrasonography diagnosis was confirmed, emphasizing the intrinsic limit of this technique in detecting large masses. Finally, pathologic review favored a diagnosis of PGL due to the morphological features and immonohistochemical profile. Eighteen months after tumor excision, the patient is asymptomatic with no disease relapse evident by either radiology or laboratory tests. Our report strongly highlights the difficulties in rendering an accurate pre-operative diagnosis of PGL.

Keywords: Peripancreatic paraganglioma; Pancreatic neuroendocrine tumor; Solid pseudopapillary neoplasm; S100; Succinate dehydrogenase subunit B gene and expression; Fine needle biopsy

Core Tip: Our report strongly supports that paraganglioma should be included in the differential diagnosis of peripancreatic/pancreatic masses, highlighting the difficulties in establishing the accurate preoperative diagnosis, even after a second-round evaluation. In fact, due to the deep localization and the lack of specific clinical manifestations and imaging data, early diagnosis often relies solely on a level of suspicion, thus making it more probable to have a missed diagnosis or misdiagnosis. Moreover, the limited time spent with a patient in an emergency setting might impair the accuracy of the diagnosis, lowering quality and outcomes of healthcare delivery. A multidisciplinary team approach, involving skilled radiologists, endoscopists, pathologists, and surgeons, is of foremost importance for proper diagnosis and management, preventing undue surgical resections.