TABLE 3.

Characteristics of Large (> 3 cm) Cystic Pancreatic Neuroendocrine Tumors (NETs)

Case No.	Cystic Change on CT	Size (cm)	Location	Peripheral Enhancementa			CT Diagnosis or Differential Diagnosis	Gross Pathology
				Arterial Phaseb	Venous Phaseb	CT Appearance (Internal Enhancing Structures)
12c	> 50%	7.9	Neck	++	++	Medium thickness and thick,  irregular (thin and medium  thickness septations)	Pancreatic NET	Contained cystic component
16	> 50%	4.7	Tail	++	+	Thin and thick, crescentic,  smooth (thin septations)	Pancreatic NET, mucinous  cystic neoplasm	Contained cystic component
17	> 50%	7.0	Body	+++	++	Thin and thick, irregular (thin  and thick septations)	Pancreatic NET	Contained cystic component,  hemorrhagic component
18c	≤50%	3.8	Head	++	+	(Predominantly solid)	Pancreatic NET	Contained cystic component
19	≤50%	13.1	Body and tail	Hypodense	Hypodense	(Predominantly solid,  hypodense)	Pancreatic NET, GIST,  sarcoma	Solid
20	≤50%	3.3	Body	++	+	Medium thickness, irregular  (predominantly solid)	Pancreatic NET	Contained cystic component,  hemorrhagic component
21	≤50%	11.1	Body and tail	+	±	Thin and thick, irregular (thin  and thick septations)	Known pancreatic NET	Contained cystic component

Note—GIST = gastrointestinal stromal tumor.

^aPeripheral enhancement was classified as smooth or irregular and as thin (≤ 3 mm), medium (> 3 and < 6 mm), or thick (> 6 mm).

^bDegree of peripheral enhancement was quantitatively graded by obtaining the difference of average attenuation of an enhancing component and of normal pancreatic parenchyma at the arterial phase and portal venous phase: − = ± 10 HU, ± = between 10 and ≤ 20 HU, + = between 20 and ≤ 40 HU, ++ = between 40 and ≤ 60 HU, or +++ = >60 HU.

^cMultiple endocrine neoplasia type 1.