Peripancreatic paraganglioma: Lesson from a round table

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.