title: Pancreatic neuroendocrine tumor with cystlike changes: evaluation with MDCT.
abstract: OBJECTIVE
  The objective of our study was to determine the prevalence and CT appearance of cystlike changes of pancreatic neuroendocrine tumor (NET), particularly of small (≤ 3 cm) tumors.
  
  
  METHODS
  The clinical records, images, and pathologic reports of 74 consecutive patients (average age, 55.5 years) with surgically resected pancreatic NETs who underwent preoperative CT were retrospectively reviewed. The size and location of the pancreatic NETs were recorded. The tumors were classified on the basis of CT appearance as small (≤ 3 cm) or large (> 3 cm) and as solid, partially (≤ 50% or > 50%) cystic, or purely (≈ 100%) cystic. Peripheral contrast enhancement on CT was characterized, and lymph node and liver metastases found by pathologic examination were recorded.
  
  
  RESULTS
  A total of 78 pancreatic NETs were reviewed. Five were not visualized on CT, leaving 73 pancreatic NETs in 69 patients (multiple tumors were visualized on CT of three patients) for analysis. The mean size of the 73 tumors was 3.0 ± 2.6 (SD) cm (range, 0.7-13.1 cm); 52 tumors were 3 cm or smaller and 21 tumors were larger than 3 cm. Gross pathologic results confirmed that 13 of the 73 (17.8%) tumors were predominantly (> 50% or ≈ 100%) cystic: 10 of the 52 (19.2%) tumors 3 cm or smaller and three of the 21 (14.3%) tumors larger than 3 cm. Peripheral contrast enhancement was seen in 11 of the 13 (85%) predominantly cystic pancreatic NETs. Compared with solid pancreatic NETs, predominantly cystic pancreatic NETs were less commonly associated with lymph node and liver metastases.
  
  
  CONCLUSIONS
  Cystic pancreatic NETs are not rare and should be included in the differential diagnosis of a cystic pancreatic mass, particularly if the cystic mass is associated with peripheral contrast enhancement. A minority of cystic pancreatic NETs can present with no peripheral enhancement.
authors: The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 601 N Caroline St, JHOC 3235A, Baltimore, MD 21287, USA. skawamo1@jhmi.edu
authors: Satomi
authors: S
authors: Kawamoto
authors: Pamela T
authors: PT
authors: Johnson
authors: Chanjuan
authors: C
authors: Shi
authors: Aatur D
authors: AD
authors: Singhi
authors: Ralph H
authors: RH
authors: Hruban
authors: Christopher L
authors: CL
authors: Wolfgang
authors: Barish H
authors: BH
authors: Edil
authors: Elliot K
authors: EK
authors: Fishman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000150:complications / Q000000981:diagnostic imaging*; D010181:Pancreatic Cyst / Q000150:complications / Q000000981:diagnostic imaging*; D010190:Pancreatic Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult