4,5,23 Certain morphological features have been used to predict particular types of pancreatic cysts. A cystic lesion with accompanying parenchymal changes, in the absence of intracystic septation or mural nodule, suggests a pseudocyst.24 The finding of multiple microcysts (< 3 mm) within a cystic lesion is suggestive of SCA.32 Occasionally, there might be a honeycomb-like area that is solid due to aggregation of small cysts in a part of the lesion.
A macrocystic-type serous cystic neoplasm might see more present with multiple lobules (Fig. 1), as in IPMN, making it difficult to differentiate between the two. If a communication between the cyst and the main pancreatic duct can be identified, that strongly suggests IPMN. On EUS, MCN usually appears as a cyst with septations of variable thickness, a visible wall, and peripheral calcifications in up to 15% of cases.33 More data have recently emerged on the role of EUS for the differentiation between benign and malignant pancreatic cysts. The clinicopathological features suggestive of malignant mucinous
cystic tumors of the pancreas that have been cited to date are shown in Table 2.6–9,28,34,35 A cyst diameter PXD101 order of greater than 3 cm was shown in a few studies to be associated with malignancy. The diameter of the main pancreatic duct that was shown to be associated with malignancy ranged widely from 5 to 15 mm, possibly
because the measurement might also include main pancreatic duct IPMN in some cases, but not in others. However, the size of the cystic lesion and main pancreatic duct diameter was not different between benign and malignant IPMN in one click here study.33 If patients were to be managed by cyst size alone, approximately 20% would have received inappropriate treatment. Therefore, some authors recommended that the size of pancreatic cystic lesions alone should not be used a sole basis for determining management.36,37 Furthermore, a study reported considerable variation in size estimates of pancreatic cysts by the different imaging modalities of CT, MRI/MRCP, and EUS, which clinicians should take into account when making management decisions, and follow up of pancreatic cysts should be with the same imaging modality, if possible.38 Thus, further studies using standardized criteria for measurements of pancreatic cystic lesions are needed to resolve this issue. Apart from cyst size, many studies have reported the index of malignancy based on the presence and size of nodules within the cysts (Fig. 2). Baba et al.