Pancreatic incidentaloma: Differentiating nonfunctioning pancreatic neuroendocrine tumors from intrapancreatic accessory spleen

Ester Osher, Erez Scapa, Joseph Klausner, Yona Greenman, Karen Tordjman, Alla Melhem, Ido Nachmany, Yael Sofer, Ravit Geva, Arye Blachar, Naftali Stern*, Erwin Santo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objective: To improve the preoperative assessment of pancreatic incidentalomas (PIs) by analysis of 1 index case and characterization of the published features of intrapancreatic accessory spleen (IPAS) compared to pancreatic neuroendocrine tumor (PNET). Methods: A search of the literature using the online database MEDLINE. Results: In all, 46 cases of IPAS have been described to date: 17 were "presumed" as IPAS based on technetium- 99m (Tc-99m) scanning, fine-needle aspiration (FNA) stain for CD8, or contrast-enhanced sonography; 29 were misdiagnosed as PNET and underwent surgery. The pancreatic lesions were 1) mostly solitary; 2) solid on imaging; 3) well defined; 4) located predominantly at the pancreatic tail; 5) not exceeding 3 cm in the largest diameter; 5) all detected in adults (22-81 years); 6) not related to sex. In subjects referred for surgery, standard imaging studies/ imaging protocols did not differentiate between IPAS and PNET. FNA was performed in 5/46 cases, all of which were false-positive for PNET. Immunohistochemical staining for T-cells on FNA material and specific imaging features (characteristic arciform splenic enhancement pattern on dynamic computed tomography [CT]; nuclear scintigraphies with radioisotope specifically trapped by splenic tissue [Tc-99m]) or contrast-enhanced sonography offered valuable clues. Still, distal pancreatectomy and splenectomy was carried out in 72%, and the rest had distal pancreatectomies. Conclusion: IPAS should be considered before surgery in patients with PIs. A new practical algorithm is presented for better preoperative evaluation of such lesions; it combines the recognition of early indicators and sequential consideration of cytologic and imaging features to decrease the hazards of unnecessary major surgery.

Original languageEnglish
Pages (from-to)773-779
Number of pages7
JournalEndocrine Practice
Issue number7
StatePublished - Jul 2016


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