Differential Diagnosis of Pancreatic Epidermoid Cyst Without a Solid Component (Residual Splenic Tissue) vs. Mucinous Cystic Neoplasm

Abstract

Purpose

The purpose of this study was to clarify whether there are differences in imaging findings between pancreatic epidermoid cyst (EDC) without a solid component (residual splenic tissue) and mucinous cystic neoplasm (MCN).

Materials and Methods

The study group consisted of histologically proven EDC (eight cases) and MCN (20 cases). CT and MRI findings were compared on the following imaging findings: the shape of the cystic lesions and the presence or absence of septum, calcification, and high-intensity fluid on T1- and diffusion-weighted images (b factor = 1000). The degree of contact with the pancreatic tail was compared between the EDCs and six of the MCNs at the edge of the pancreatic tail.

Results

The EDCs were round (n = 3) or oval (n = 5), while the MCNs consisted of three round, five oval, six pear-like, and six multilobulated lesions (P < 0.05). Septum was present in 4 of 8 (50%) EDCs and 19 of 20 (95%) MCNs (P < 0.05). The presence of calcification (2 of 8 [25%] EDCs vs. 8 of 20 [40%] MCNs), high-intensity fluid on T1-weighted images (2 of 7 [29%] EDCs vs. 5 of 20 [25%] MCNs), and high-intensity fluid on diffusion-weighted images (5 of 7 [71%] EDCs vs. 5 of 20 [25%] MCNs) were not significantly different. The degree of contact with the pancreatic parenchyma was similar between the two types of lesions.

Conclusion

Although the imaging findings for EDC without a solid component and MCN overlap, a pear-like or multilobulated shape may favor a diagnosis of MCN.

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