PMC5216141_01
Dynamic computed tomography reveal a mass measuring 3 cm in size in the pancreatic tail with a cystic lesion and a solid component located on the periphery that is enhanced in the arterial phase. The densities of the solid component and spleen are very similar (a: plain, b: arterial phase, c: portal phase, d: delayed phase).
1349-7235-55-3445-g001.jpg
PMC5216141_01_1349-7235-55-3445-g001.jpg
g001
Contrast-enhanced computed tomography (CT) revealed a mass measuring approximately 3 cm in size in the pancreatic tail with a cystic lesion and solid component located on the peripheral tumor that was enhanced in the early phase (Fig. 1).
Magnetic resonance images reveal that the intensity of the solid component on T1 weighted image and T2 weighted image is closely similar to that of the spleen and different from that of the pancreatic parenchyma (a: T1WI in phase, b: T1WI out of phase, c: T2WI, d: Diffusion WI).
1349-7235-55-3445-g002.jpg
PMC5216141_01_1349-7235-55-3445-g002.jpg
g002
Magnetic resonance imaging (MRI) revealed that the cystic lesion was iso-intense on the T1-wighted image (WI) and hyper-intense on the T2-WI; the solid component was hypo-intense on T1-WI and slightly high on T2-WI (Fig. 2).
Curved linear array endoscopic ultrasonography demonstrating a slightly high echoic component compared to the pancreas parenchyma, with a cystic lesion (a). It was difficult to puncture the mass while avoiding the rich perfusion of blood vessels around the mass lesion (b).
1349-7235-55-3445-g003.jpg
PMC5216141_01_1349-7235-55-3445-g003.jpg
g003
On endoscopic ultrasonography (EUS), a round-shaped mass had a slightly high echoic solid component compared to the pancreas parenchyma, with a cystic lesion (Fig. 3a). EUS guided fine needle aspiration biopsy (EUS-FNA) was not performed, because it was difficult to puncture the mass while avoiding the rich perfusion of vessels around the mass lesion (Fig. 3b).
The resected specimen reveals a well-demarcated 3 cm mass at its greatest diameter and a 1.5cm multicystic lesion with brownish fluid (a). The solid component includes splenic tissue with typical red and white pulp [b: Hematoxylin and Eosin (H&E) staining, x10 magnification, c: H&E staining, x40]. The cyst was multicystic and lined with a multilayered (two to five layers) epithelium (b: H&E staining, x10, d: H&E staining, x40).
1349-7235-55-3445-g004.jpg
PMC5216141_01_1349-7235-55-3445-g004.jpg
g004
The resected specimen revealed a well-demarcated 3 cm mass at its greatest diameter and a 1.5 cm multicystic lesion with brownish fluid (Fig. 4a). Microscopically, the solid component included splenic tissue with typical red and white pulp (Fig. 4b and c). The cyst wall was mainly composed of non-keratinized stratified squamous epithelium without any skin appendage (Fig. 4b and d), and the squamous epithelium was covered with a hobnail-like growth epithelium.
The squamous epithelium of the cyst wall is positive for CK5/6 (a:x200) and p63 (b:x200).
1349-7235-55-3445-g005.jpg
PMC5216141_01_1349-7235-55-3445-g005.jpg
g005
In an immunohistochemical (IH) analysis, the squamous epithelium of the cyst wall showed positive findings for CK5/6, p63 (Fig. 5), and negative findings for CK7, vimentin and muscle actin.