J Korean Soc Radiol.  2018 Mar;78(3):163-169. 10.3348/jksr.2018.78.3.163.

Imaging Findings of Pancreatic Solid Pseudopapillary Neoplasm with High-Grade Malignant Transformation: Focusing on Diffusion-Weighted Imaging and Normalized Apparent Diffusion Coefficient Values

• Kang KR
• Shin OR
• Lee SL
• Ku YM

• KMID: 2405718
• DOI: http://doi.org/10.3348/jksr.2018.78.3.163

Abstract

Solid pseudopapillary neoplasm (SPN) of the pancreas is an uncommon neoplasm characterized by low-grade malignant potential and uncertain histogenesis, and usually afflicts relatively young women. The tumors typically manifest as well-marginated, mixed density lesions consisting of a solid peripheral and central cystic component in conjunction with hemorrhagic foci. SPN with apparent high-grade malignant transformation is a rare histologic variant. Herein, we report a rare case of SPN with high-grade malignant transformation diagnosed in a 75-year-old female, with emphasis on differential diagnoses and role of normalized ADC values. SPN with malignant transformation should be included in the differential diagnosis in cases of mixed solid and cystic masses with hemorrhagic components, irregular margin and lower normalized apparent diffusion coefficient (ADC) values in an elderly female patient, as was the case discussed below.

MeSH Terms

Aged
Diagnosis, Differential
Diffusion Magnetic Resonance Imaging
Diffusion*
Female
Humans
Magnetic Resonance Imaging
Pancreas
Pancreatic Neoplasms

Figure

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  Fig. 1. A 75-year-old female patient presented a pancreatic solid pseudopapillary neoplasm with high-grade malignant transformation. A. Contrast-enhanced axial computed tomography image demonstrates about 9.2 × 6.6 × 7.0 cm sized relatively well-demarcated lobulated mixed density mass in the tail of the pancreas, composed of enhancing solid component peripherally (solid arrows) and non-enhancing cystic component centrally (open arrow). B. The MRI shows heterogeneous low to intermediate signal intensity with some central high signal intensity foci (open arrow) on T1-weighted image (left column), heterogeneous intermediate to high signal intensity with internal low signal intensity areas (solid arrow) on T2-weighted images (right column). C. On the dynamic MRI, the mass shows heterogeneous peripheral enhancement in the arterial phase (left column), and heterogeneous peripheral gradual enhancement with internal non-enhancing cystic portion in the delayed phase (right column). D. On diffusion-weighted imaging, the intensity is high, with a high b value (800 sec/mm2) (upper row) and low signal intensity on apparent diffusion coefficient mapping (lower row). MRI = magnetic resonance image A 75-year-old female patient presented a pancreatic solid pseudopapillary neoplasm with high-grade malignant transformation. E. Microscopic findings shows that the tumor cells are radially arranged with papillary configurations composed of delicate and somewhat hyalinized fibrovascular core on the necrotic background (solid arrows) with cellular pleomorphic and numerous mitosis (open arrow) (hematoxylin and eosin stain, × 40). F. Immunohistochemical staining shows that the tumor cells are positive for alpha-1-antitrypsin (left column) and vimentin (right column) (immunohistochemical stain, × 200).

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Reference

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