Extremely rare case of acute edematous pancreatitis associated with an incidental pancreatic lipoma

Case report: A 60-year-old woman was admitted to the Hospital because of intense epigastric pain, nausea and vomiting. Her previous medical history was negative. The physical examination revealed epigastric tenderness and positive Murphy's sign. Laboratory tests showed neutrophilic leukocytosis, high ESR, amylase and lipase. Gamma-GT, alkaline phosphatase, total and direct bilirurbin were in the normal range. Ultrasound showed an oval shape and hypoechoic lesion with maximum size of 2.5 cm, located in the head of pancreas; the organ had blurred margins and was increased in size. Color Doppler sonogram did not reveal vascularity inside the lesion. Neoplastic markers, such as CEA and CA 19.9, were negative. Further investigation was mandatory. On Computer Tomography (CT), the lipoma appeared as a well-circumscribed lesion with density values characteristic for adipose tissue, while on Magnetic Resonance Imaging (MRI) it demonstrated high and decreased signal intensity on T1- and T2-weighted images, respectively. The diagnosis of acute pancreatitis associated with an incidental pancreatic lipoma was made. The patient underwent conservative treatment with benefit.

Discussion: Pancreatic lipomas are extremely rare non-epitelial tumors: so far, less than twenty-five cases have been described in the literature. They arise from mesenchymal tissue and are usually asymptomatic. The pathophysiology is unclear; the entrapment of adipose tissue during the posterior rotation of the ventral pancreatic bud has been proposed as the leading theory. While ultrasound constitute the first investigation, CT and MRI are mandatory to exclude malignant tissue and avoid any bioptic approach in a large percentage of cases. Finally sonography is useful in the follow-up of patients conservatively treated.