MRI features of solid pseudopapillary neoplasm of the pancreas

To evaluate the magnetic resonance imaging (MRI) findings of solid pseudopapillary neoplasm (SPN) of the pancreas.

From January 2006 to December 2013, 41 patients with SPN of the pancreas were retrospectively evaluated. Inclusion criteria were the execution of an MR examination and tumor resection with an histopathological evaluation at our Institute. Exclusion criteria were the execution of an MR examination at other centers (14/41) and the execution of CT or ultrasonography (10/41) at our Institute. The qualitative analysis evaluated: location (head/body-tail), shape (round/oval/lobulated), margins (regular/irregular), and signal intensity on T1- and T2-weighted images compared to the surrounding pancreas (hypo-, iso-, or hyperintense and homogeneous or heterogeneous), appearance of MPD and the secondary ducts, and the presence of metastases and/or vascular involvement. The quantitative analysis included: maximum size of the lesion, wall thickness, and maximum diameter of the main pancreatic duct (MPD).

The population comprised 17 women (median age: 31 year) with a median tumor size of 50.6 mm, a median wall thickness of 2 mm and median diameter of the MPD of 1.8 mm. 9/17 were at the head; 8/17 on the body/tail: respectively, 8/17 round, 6/17 oval, and 3/17 lobulated. All showed regular margins. On T1-weighted images 8/17 appeared homogeneously hypointense, 7/17 heterogeneously hypointense, and 2/17 heterogeneously hyperintense. On T2-weighted images 1/17 appeared homogeneously hyperintense and 16/17 heterogeneously hyperintense. No secondary ducts dilatations were detected. During the follow-up, one patient presented disease recurrence 48 months after surgery.

MR imaging features can be highly suggestive for the diagnosis of SPN.