Rare pancreatic neoplasm: MDCT and MRI features of a typical solid pseudopapillary tumor

Abstract

Solid pseudopapillary tumor of the pancreas is a rare neoplasm, predominantly observed in young women and with greatest incidence in the second and third decade. It has clinically good behavior, although large at the time of diagnosis. We report the case of a thirty-year-old woman with a giant mass in the pancreas, incidentally discovered during an abdominal ultrasonography. The mass was later investigated by multidetector computed tomography and magnetic resonance imaging. The cystic-solid appearance of the encapsulated lesion suggested to radiologists the possibility of a solid pseudopapillary tumor. Imaging features of this pancreatic neoplasm and differential diagnosis from other cystic pancreatic tumors are discussed in our report, in order to help radiologists and clinicians achieve correct diagnosis and management.

Keywords: Carcinoma; Frantz-Gruber tumor; Gruber-Frantz tumor; Magnetic Resonance Imaging; Pancreas; Pancreatic Neoplasms; Papillary/diagnosis; Tomography; X-Ray Computed.

Figure 1

A thirty-year-old female with a typical solid pseudopapillary tumor. Ultrasonography was performed using a 3.5 Mhz convex transducer; color-Doppler (figure A) and grayscale (figure B) images were acquired (kindly provided by patient; also courtesy of Dr. Giuseppe Di Bella of “Centro di Epatogastroenterologia e nutrizione”, Giarre). Images A and B show a lobulated mass (white arrow) centered on the body of the pancreas, with round-shaped cystic appearance; the mass is well defined and contains multiple echoic intralesional areas - due to the presence of solid components.

Figure 2

A thirty-year-old female with a typical solid pseudopapillary tumor. Computed tomography - unenhanced (2a) and enhanced images (2b and 2c, respectively arterial and portal phases), obtained by a multidetector scanner (Protocol: 140 Kv, 250 milliamperes, slice thickness = 2.5 mm, contrast medium Iomeprolo 400 mg/ml, total dosage of contrast 120 ml). The images show a large mass (white arrow) centered on pancreatic parenchyma; in figure 2a the mass appears slightly hypodense. After contrast administration (figure 2b and figure 2c) there is a slow fill-in enhancement, suggesting the presence of intralesional solid components. In the venous phase - figure 2c - a cystic area (asterisk) appears in the large mass.

Figure 3

A thirty-year-old female with a typical solid pseudopapillary tumor. Fig. 3 A. Axial fast spin echo image with fat saturation - TR= 2100 msec, TE= 98.5 msec, thickness 6 mm, spacing 1 mm - obtained by a 1.5 Tesla GE Signa HDxt scanner. MRI shows the presence of the pancreatic mass (white curved arrow in Fig. 3a) and clearly demonstrates the solid intralesional components. Fig. 3b. Coronal T2-weighted single-shot spin echo image - TR= 715 msec, TE= 92.5 msec, thickness 5 mm, spacing 1 mm - obtained by a 1.5 Tesla GE Signa HDxt scanner. The image shows a lobulated pancreatic mass, which contains multiple internal slightly hypointense solid areas. The lesion is limited by a continuous capsule - which appears hypointense on image (white arrowhead). Axial unenhanced image (Fig. 3c), axial enhanced image (Fig. 3d) and coronal enhanced image (Fig. 3b), obtained by a T1-weighted 3D fast spoiled gradient echo image - TR = 4.3 msec, TE = 2.1 msec, thickness = 3 mm - using a 1.5 Tesla GE Signa HDxt scanner. After contrast administration (Gadobenate dimeglumine 0.5 M, at a dosage of 0.1 mmol/kg) MRI clearly demonstrates the solid content thanks to its excellent contrast resolution; there is a slow fill-in enhancement (white arrow), due to the presence of intralesional solid components.

Figure 4

A thirty-year-old female with a typical solid pseudopapillary tumor. Solid-pseudopapillary neoplasm microscopic findings on our biopsy specimen (Haematoxylin eosin, 20× high power field): prominent pseudopapillary growth pattern; pseudopapillae are formed when neoplastic cells drop away, leaving a variable number of cells surrounding delicate capillary-sized blood vessels.