Chronic follicular pancreatitis: a space occupying lesion with spontaneous resolution.

Follicular pancreatitis (FP) is an extremely odd entity characterized by the presence of a pseudotumor that histologically presents lymphoid aggregates and germinal centers. The authors present the case of a 67-year-old woman with epigastric pain and jaundice. Endoscopic ultrasonography (EUS) was performed, revealing a 14x15 mm hypoechoic area with irregular edges in the head of the pancreas. The in situ cytological study showed polymorphic lymphoid cellularity, without atypia suggesting neoplasia. The cell block and the immunohistochemical study showed a polyclonal population with a pattern suggestive of FP. The patient presented spontaneous clinical improvement. The EUS follow up three months later shown pancreatic parenchyma with homogeneous echogenicity and no space occupying lesions were indentified. Since the diagnosis of FP has been reached after surgery in most cases, the treatment is not well established. However, no recurrences have been reported after surgery and spontaneous resolution has been observed in incomplete resections, which suggests the indication for conservative management. Diagnostic EUS has a fundamental role in the differential diagnosis between FP and pancreatic neoplasms, two entities with very different prognosis, and makes it possible to avoid, in the case of FP, unnecessary surgeries with the associated morbidity and mortality.