Diminishing calcifications as a potential predictor of pancreatic ductal adenocarcinoma arising in association with IPMN in patients with chronic pancreatitis

Abstract

Chronic pancreatitis (CP) is a progressive benign fibroinflammatory condition involving repeated episodes of pancreatic inflammation, which lead to fibrotic tissue replacement and subsequent pancreatic insufficiency. A lifetime risk of developing pancreatic ductal adenocarcinoma (PDAC) in patients with chronic pancreatitis is reported to be 1.5%-4%. However, diagnosis of PDAC in patients with CP can be challenging, in part due to overlapping imaging features. In rare instances, pancreatic parenchymal calcifications that are typically associated with chronic pancreatitis may diminish in the case of a developing PDAC. In this article, we present a patient with chronic pancreatitis in whom calcifications decreased at the time of pancreatic ductal adenocarcinoma diagnosis, as compared to prior CT imaging. The unique imaging features of "diminishing calcifications" associated with a hypoattenuating lesion can potentially be a useful sign of pancreatic ductal adenocarcinoma and may aid in early diagnosis and prompt treatment intervention.

Keywords: Chronic pancreatitis; Computed tomography; Diminishing calcification; Intraductal papillary mucinous neoplasm; Pancreatic ductal adenocarcinoma; Pancreatic neoplasms.

Fig. 1

Contrast enhanced (A) axial and (B) oblique coronal reformatted CT images show severely atrophic pancreas with diffuse calcifications, compatible with chronic pancreatitis. (C) Coronal and (D) oblique coronal maximal intensity projection images show diffuse calcifications throughout the pancreas. Inferior vena cava filter overlapping the pancreatic head on (C) coronal image.

Fig. 2

Contrast enhanced (A) axial and (B) oblique coronal reformatted CT images show interval development of ill-defined heterogeneous hypodense enlargement of body and tail of the pancreas (yellow arrowheads) with scattered cystic lesions. Loss of fat plane between the enlarged pancreas and stomach is well appreciated on oblique coronal image. Calcifications in body and tail are decreased compared to Figure 1. (C) Coronal and (D) oblique coronal maximal intensity projection images show diffuse calcifications throughout the pancreas, but body and tail calcifications in the area of enlargement are decreased compared to Figure 1. Diffuse vascular calcifications involving aorta, iliac artery, splenic and renal arteries developed secondary to end stage renal disease. Pancreatic duct stent and inferior vena cava filter are seen overlapping with the pancreatic head.

Fig. 3

Volumetric representation showing the distribution of pancreatic calcifications in the original CT scan (A) and the follow-up scan (B). Calcification volume was quantified by counting voxels within the pancreatic parenchyma with a HU value above 160 in the arterial phase. The percentage was calculated based on the total voxel count within the pancreatic parenchyma. CT: computed tomography; cc: cubic centimeters; HU: Hounsfield units.