Cavernous hemangioma of an intrapancreatic accessory spleen mimicking a pancreatic tumor: A case report

Table 1 Clinical and radiological characteristics of intrapancreatic accessory spleen and pancreatic cystic neoplasms

		Pancreatic cystic neoplasms
	IPAS	Pseudocyst	SCA	MCA	SPN	IPMN
Clinical features[1,17,18]
Age (mean: year)	40 to 65	At any age	60	40 to 50	30	65
Gender	Slightly higher in males	Males > females	Older females	Females > males	Young females	Males > females
Incidence	11%–17% of AS	5%-40% after pancreatitis	16% of PCN	29% of PCN	2% and 3% of PCN	20%-50% of PCN
Benign/malignant	Benign	Benign	Benign	Low malignant potential	Low malignant potential	Malignant potential
Anatomic location	Tail > head/body	1/3 near the head	Head > body/tail	Body/tail > head	Body/tail > head	Arising from the pancreatic ducts
Size (mean: cm)	≤ 2	Depending on the duration of disease	5-8	7-10	6	0.8
Potential mimickers	NET and PDAC	MCA	MCA and IPMN	MCA: IPMN and MCAC	MCA: IPMN and MCAC	SCA: MCA and MCAC
Radiological diagnosis
Ultrasound[7,17,19-21]
Baseline US	Hypoechoic lesion with well-defined border	Transonic: net separation: irregular internal outline: fluid-containing lesion	Small transonic lesions with thin septa inside	Unilocular or septated cystic lesions with thickened walls and well-defined margins	Encapsulated mixed mass (solid and cystic)	Lesions developed inside the main/branch pancreatic ducts: parietal nodules and septa can be seen in the cysts
Doppler US	Blood supply may from the splenic vessels	No obvious blood flow encompass or inside the lesion	No obvious blood flow encompass or inside the lesion	No obvious blood flow encompass or inside the lesion	Blood flow signal around the tumor	No obvious blood flow encompass or inside the lesion
CEUS[19,21]	Inhomogeneous hyperenhancement followed by homogeneous hyperenhancement	Iso- or hyperenhancement of the cystic wall: without definite washout	Isoenhancement of the cystic walls and septa: without definite washout	Iso-enhancement of the cystic walls and nodules: without definite washout	Rim hyperenhancement in the capsule:centripetal hyperenhancement followed by mild washout in the solid part: no enhancement in the cystic components	Iso-enhancement in the cystic wall and nodules
CECT[18,21-23]	Inhomogeneous hyperenhancement followed by homogeneous hyperenhancement	Round or oval fluid collection with a thin: hardly perceptible wall or enhancing thick wall	Well-defined: polycystic or honeycomb lesions showing enhancing internal septa and cyst walls	Well-circumscribed round/oval macrocystic lesions with enhancement of the walls	Hypo-attenuating on pancreatic phase followed by homogeneous gradual enhancement to iso-attenuating on the hepatic venous phase	Dilated main/side pancreatic ducts: nodules arising from the ducts manifest hyperattenuating at contrast-enhanced CT
CEMRI[22,24]
T1-W	Inhomogeneous hypointensity	Blood products and necrotic components commonly present intrinsically increased t1 signal intensity: the thickend wall shows a rim hyperintensity	High intensity fluid in the cysts	Homogeneous low t1 signal intensity	Low signal intensity: SPN with hemorrhage presents t1 hyperintensity	Loss of t1 signal and delayed uptake of contrast material
T2-W	Homogeneous hyperintensity	The hyperintensity in tissues surrounding the pseudocyst represents the inflammation on t2 fat-suppressed images	Honeycomb pattern (microcysts) or macrocysts manifest signal intensity of simple fluid	Homogeneous high t2 signal intensity	Predominantly solid show mildly increased t2 signal intensity: cystic-dominated present t2 signal intensity closer to that of fluid	Papillary excrescences or nodules in the walls of the dilated ducts present hypointense on t2-weighted images
Management	Usually require no treatment	Serial imaging follow-up	Follow-up or resection depending on the size of the tumor	Surgical resection	Surgical resection	Recommended to be surgically resected

AS: Accessory spleen; IPAS: Intrapancreatic accessory spleen; PCN: Pancreatic cystic neoplasm; SCA: Serous cystadenoma; MCA: Mucinous cystadenoma; SPN: Solid pseudopapillary neoplasm; IPMN: Intraductal papillary mucinous neoplasm; MCAC: Mucinous cystadenocarcinoma; US: Ultrasound; CEUS: Contrast enhanced ultrasound; CECT: Contrast enhanced computerized tomography; CEMRI: Contrast enhanced magnetic resonance imaging; T1-W: T1-weighted; T2-W: T2-weighted.