A well-differentiated, invasive ductal adenocarcinoma in the pancreatic body

A 69-year-old male patient, complaining of abdominal pain and discomfort slowly progressing over the past three months, came to the hospital for a check-up. The patient had a new onset of diabetes mellitus. Ultrasound examination revealed a partially solid and partially cystic mass in the pancreatic body, with suspicious invasion into the gastric wall. A contrast-enhanced CT examination was requested and performed with a dual source, photon-counting detector (PCD) CT, NAEOTOM Alpha®, for further local assessment of the pancreatic mass and disease staging.

CT images showed a well-defined, exophytic mass in the pancreatic body, causing obstruction with upstream dilatation of the main pancreatic duct. The mass, measuring 4.5 cm x 4.6 cm in size, was hypoattenuating in the virtual non-contrast (VNC) images, and hypovascular in the arterial and portal-venous contrast phases. Virtual monoenergetic images (VMI) displayed at 40 keV showed an increased contrast enhancement, resulting in an improved visualization of a brighter rim of the tumor adjacent to the gastric wall and the fatty tissue between the tumor and the gastric wall. This indicated the likelihood of a desmoplastic reaction rather than an invasion of the tumor. There was no evidence of vascular encasement. The celiac artery (CA), the superior mesenteric artery (SMA) and the portal vein did not show CT-signs of invasion. No metastases of the liver or local lymph nodes were seen, neither on CT, nor on liver MRI. A subsequent endoscopic ultrasound examination revealed no tumor invasion into the gastric wall. After completed staging, imaging findings suggested a resectable pancreatic ductal adenocarcinoma (PDAC), stage IIa, T3 N0 M0.

The patient underwent surgical resection of the tumor. CT findings were intra-operatively confirmed. A post-operative pathological evaluation confirmed a complete tumor resection with free resection margins (R0). A histological analysis revealed a well-differentiated invasive ductal adenocarcinoma. The patient continued with neoadjuvant chemotherapy and has been, to-date, free from recurrence.

Fig. 2: Cinematic VRT images show a three-dimensional view of the tumor (Fig. 2a–2c) and the arteries (Fig. 2d). The tumor is located in the pancreatic body (arrows), showing no evidence of gastric wall invasion. Normal branches of the CA and the SMA are shown, without variation or stenoses.

PDAC is the most common pancreatic malignancy, accounting for more than 85% of pancreatic tumors, with poor prognosis and rising incidence. In early stages, it is usually asymptomatic. Approximately 80% of the cases are diagnosed at an advanced stage (T3 or T4). [1] The only potential curative treatment is a complete surgical resection. [2] Therefore, a careful pre-operative assessment is crucial for an upfront patient stratification. CT is considered the modality of choice for tumor staging. Pre-operative evaluations on vascular variations and stenoses are also important for the surgeons, allowing for a proper surgical planning, avoiding intraoperative vascular injuries and postoperative complications.

PCD-CT provides energy-resolved CT data with increased spatial resolution and inherent spectral information. [3] VMI can be reconstructed and displayed at different keV levels in routine scans. The tissue contrast is increased in VMI displayed at 40 keV compared to VMI displayed at 70 keV (equivalent to a standard image acquired at 120 kV) and is further optimized by a combination of missing down-weighting of the lower energy X-ray photons and absence of electronic noise. As shown in this case, the combination of increased spatial resolution and tissue contrast is beneficial for the visualization of a thin rim of the tumor and the fatty tissue between the tumor and the gastric wall. This helps enhancing physician’s confidence in differentiating desmoplastic reaction from tumor invasion, critical for assessment on tumor resectability, and subsequently, patient’s outcome.