Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine guidelines: Rare pancreatic tumors, ultrasound and contrast-enhanced ultrasound features-Malignant mesenchymal tumors

Abstract

Rare malignant mesenchymal pancreatic tumors are systematized and reported in this review. The focus is on the appearance on imaging. The present overview summarizes the data and shows that not every pancreatic tumor corresponds to the most common entities of ductal adenocarcinoma or neuroendocrine tumor.

Keywords: Imaging; Malignant mesenchymal pancreatic tumors; Pancreatic EGIST.

Figure 1

Extragastrointestinal stromal tumor at the pancreatic head. Display of the GIST tumor on the right side and the normal pancreatic head on the left side. The scan was taken from the descending duodenum. Unenhanced Doppler color display is overlaying the gray scale scan (A). The hypoechoic tumor is visible with the result of the elastographic scanning on the left side. The tumor appears blue that means harder than the surrounding tissue (B). Contrast-enhanced harmonic EUS with 4,8 mL SonoVue. The typical highly vascularized tumor and the central necrosis are visible (C). The tumor is displayed using 3D reconstruction after injection of 4,8 mL SonoVue in CEH-EUS (D). The same tumor in a 3D reconstruction of a color Doppler mode overlying gray-scale ultrasound. The surrounding vessels are clearly visible (E). Pulsed-Wave (PW)-Doppler mode after injecting of 4.8 mL SonoVue in high-mechanical-index EUS, only high-resistance arterial vessels can be detected within the tumor (F). Cytological result after endosonographic fine-needle puncture of the tumor. Typical mesenchymal tumor cells are displayed (H).

Figure 2

A 76-year-old man presented after a fall and a trauma series. Computed tomography scan (A) demonstrated a large, complex cystic mass between the pancreatic tail and the spleen. Initially felt to be a hemorrhagic lesion following the recent trauma, the complexity of the lesion prompted MRI evaluation. The MRI (B) demonstrated the lesion to arise from an expanded pancreatic tail. The fluid contents of the lesion appeared of intermediate high signal on T1 suggestive of hemorrhagic or proteinaceous characteristic and with more solid components within the peripheries of the lesion. Percutaneous ultrasound-guided drainage of the lesion yielded serous fluid for analysis, although cytological results did not demonstrate any malignancy. The patient underwent an EUS (C), which demonstrated a large mixed cystic/solid lesion and FNB of the solid components confirmed the diagnosis of high-grade leiomyosarcoma.

Figure 3

A 28-year-old man presented with general malaise, weight loss, and jaundice. A large palpable mass was discernible in the epigastrium on abdominal examination. Computed tomography scan (A) demonstrated a 12-cm lobulated mass arising from the head of the pancreas causing biliary and pancreatic duct obstruction. EUS (B) demonstrated a heterogeneous soft tissue mass lesion with some cystic foci, and FNB was performed. PET-CT (C) showed intense tracer (¹⁸F-FDG) uptake.

Figure 4

A 30-year-old man who was diagnosed with rhabdomyosarcoma of the skull base with bone and lymph node metastases 2 years previously presented with jaundice. He underwent a CT (A) scan demonstrating a diffusely abnormal pancreas with biliary obstruction with no focal pancreatic lesions seen and no adjacent peripancreatic fluid or inflammatory stranding. A PET-CT (B) showed diffuse ¹⁸F-FDG uptake throughout the pancreatic parenchyma. An ERCP and biliary stenting (C) were performed, and cholangiogram demonstrated stricturing of the entire intrapancreatic portion of the extrahepatic common bile duct. EUS-FNB (D) was performed concurrently with ERCP and demonstrated the pancreas gland to be diffusely abnormal and expanded in its entirety with multiple hyperechoic foci. Histology confirmed diagnosis of metastatic rhabdomyosarcoma to the pancreas.