A 68-year-old female patient presented with nonspecific abdominal pain and early satiety. Laboratorial tests revealed normal liver function and carbohydrate antigen 19-9 (Ca19.9), as well as an elevated serum amylase (163 U/L). The patient had a prior history of hypertension, type 2 diabetes mellitus and dyslipidemia. An abdominal computed tomography (CT) scan showed a pseudonodular area measuring 12x11mm (axial), with arterial phase hyperenhancement, located in the anterior part of the transition between the body and tail of the pancreas (Fig. 1).
Endoscopic ultrasound (EUS) identified a hypoechoic, homogeneous, round, vascular, well-circumscribed solid nodular lesion, measuring 10×10 mm (Fig. 2 and 3).
The lesion did not communicate with the main pancreatic duct. An EUS-guided fine-needle aspiration (FNA) using a 25G needle was performed with three passes (Fig. 4).
What is the most likely diagnosis?
FNA cytology showed small clusters of cells with salt-and-pepper chromatin nuclei, positive for cytokeratin AE1/AE3 and synaptophysin. The findings were compatible with pancreatic neuroendocrine tumor (pNET). Immunocytochemistry revealed a Ki67 index <1%. The patient also had an elevated serum chromogranin A (108 ng/mL). Positron emission tomography (PET 68Ga-DOTANOC) confirmed a hypermetabolic nodular lesion, without further enhancements. Considering the size and grade of the tumor, the patient was proposed for surveillance. However, considering the patient individual decision, a distal pancreatectomy with complete resection of a non-functional grade 1 pNET was performed.
Increasing numbers of pNET are being diagnosed incidentally during radiologic or endoscopic studies . EUS with FNA is an effective method to provide an accurate identification of pNET, although contrast-enhanced ultrasonography may improve the diagnosis capacity . Moreover, immunocytochemical studies offer additional information, allow grading of the tumor and support differential diagnosis between other pancreatic neoplasms and metastatic lesions . However, optimal management of asymptomatic, small (<2 cm) and low grade pNET still remains controversial .
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Margarida Flor de Lima1, Nuno Nunes1, Diogo Bernardo Moura1, Vera Costa Santos1, Maria Antónia Duarte1.
- Gastroenterology Department, Hospital do Divino Espírito Santo de Ponta Delgada, Ponta Delgada, Portugal.