The computed tomography (CT) appearance of SCA depends on the macroscopic feature of the tumor and on the timing of data acquisition. Microcystic tumors are seen as an unenhanced mass, sometimes deforming the profile of the gland, when peripherally located. The density is homogeneous and may be the same or slightly superior to that of water but more frequently hypodense compared to adjacent pancreatic parenchyma (Fig. 2.2). Calcifications may occur in 30% of the cases; when present, they are centrally located (Fig. 2.2) and punctate or globular, as opposed to the lamellar calcifications seen in mucinous cystic tumors [5]. A central fibrous scar is visible in 47% of the cases, especially in larger masses since it forms later in tumor development (Fig. 2.2). Maximal visualization of the septa is possible on contrast-enhanced CT in the pancreatic parenchymal phase as well as based on the honeycomb appearance. A cystic mass with a central calcification in conjunction with a central scar is highly indicative of SCA. In the mixed forms, peripheral macrocysts are even more easily recognizable on CT than by US, making the diagnosis easier. In the delayed phase of contrast enhancement, septal recognition is very difficult due to the intracystic liquid. Macrocystic patterns are indistinguishable from other macrocystic masses of the pancreas, such as mucinous cystic tumors.

Magnetic resonance imaging (MRI) is increasingly assuming a major role in the work up of these patients due to its capability to simultaneously assess the pancreatic parenchyma and the pancreatic ductal system. In the microcystic pattern of SCA, even a small content of fluid within the dense septa of a “sponge-like” mass can be seen on MRI; however, this technique has the disadvantage that it is insensitive to calcifications [6] (Fig. 2.3). In macro-microcystic forms, the two components are well recognizable. An even better evaluation of the spatial relation between the mass and the biliary or pancreatic duct is obtained with magnetic resonance cholangiopancreatography (MRCP), which distinguishes these tumors from intraductal papillary mucinous neoplasms (IPMNs), particularly when the tumor is located in the head or the uncinate process of the gland. MRCP should be routinely carried out in the staging of these tumors since it helps to distinguish microcystic SCA from intraductal tumors of the peripheral branches, with their septate appearance [7]. The presence/absence of communication with the pancreatic duct system is diagnostic and is useful for the differential diagnosis between SCA and IPMN.

In the oligocystic forms of SCA, the MRI aspects are non-specific and do not lead to a definitive differential diagnosis from mucinous forms.