title: PANCREATIC INCIDENTALOMA: DIFFERENTIATING NONFUNCTIONING PANCREATIC NEUROENDOCRINE TUMORS FROM INTRAPANCREATIC ACCESSORY SPLEEN.
abstract: 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).
  
  
  
  A search of the literature using the online database MEDLINE.
  
  
  
  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.
  
  
  
  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.
  
  
  
  CT = computed tomography EUS = endoscopic ultrasound FNA = fine-needle aspiration HDRBC = heat-damaged red blood cells IPAS = intrapancreatic accessory spleen MRI = magnetic resonance tomography NF-PNET = nonfunctioning pancreatic neuroendocrine tumor PET = positron emission tomography PNET = pancreatic neuroendocrine tumor PI = pancreatic incidentalomas SPIO = superparamagnetic iron oxide Tc-99m = technetium-99m.
authors.forename: Ester
authors.initials: E
authors.lastname: Osher
authors.forename: Erez
authors.initials: E
authors.lastname: Scapa
authors.forename: Joseph
authors.initials: J
authors.lastname: Klausner
authors.forename: Yona
authors.initials: Y
authors.lastname: Greenman
authors.forename: Karen
authors.initials: K
authors.lastname: Tordjman
authors.forename: Alla
authors.initials: A
authors.lastname: Melhem
authors.forename: Ido
authors.initials: I
authors.lastname: Nachmany
authors.forename: Yael
authors.initials: Y
authors.lastname: Sofer
authors.forename: Ravit
authors.initials: R
authors.lastname: Geva
authors.forename: Arye
authors.initials: A
authors.lastname: Blachar
authors.forename: Naftali
authors.initials: N
authors.lastname: Stern
authors.forename: Erwin
authors.initials: E
authors.lastname: Santo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002828:Choristoma / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013154:Spleen; D055815:Young Adult