Mucinous cystadenoma constitutes approximately 23% of all the resected cystic lesions of pancreas, and serous cystadenoma accounts for 16% [19]. Mucinous cystadenoma has considerable malignant potential, estimated to be between 10% and 50% [20]. In contrast, serous cystadenoma is considered benign and are typically found incidentally. A large multicenter study found only 3 cases of serous adenocarcinoma in a series of 2622 patients with serous cystadenoma, suggesting that serous cystadenomas are almost always benign and indolent tumors [21]. Thus, surgical intervention should be proposed in a minority of patients with serous cystadenoma, only for those who had uncertain diagnosis after systemic examinations or had symptoms [21, 22]. Given the risk of invasive disease and the relatively young age at diagnosis, surgical management is recommended for all mucinous cystadenoma patients who are medically fit for the surgery [23]. Therefore, the differential diagnosis of the two diseases is clinically crucial for the choice of treatment regimen.
Although CT images enable the correct diagnosis in typical cases, serous cystadenoma, especially macrocystic or oligocystic types, are difficult to distinguish from mucinous cystadenoma [24]. Previous studies have reported many cases of pancreatic serous cystadenoma that are misdiagnosed as mucinous cystadenoma and therefore are inappropriately managed [24-26]. In this study, the results showed that morphological features and textural parameters, including location, size, lobulated contour, SHAPE_Volume (mL), SHAPE_Volume (# vx), GLRLM_HGRE, GLRLM_SRHGE, GLRLM_LRHGE, GLRLM_GLNU, GLRLM_RLNU, GLZLM_LZE, GLZLM_LZHGE, GLZLM_GLNU and GLZLM_ZLNU were significant differentiators of pancreatic mucinous cystadenoma and serous cystadenoma. Furthermore, the combination of morphological and textural features demonstrated good ability to discriminate the two diseases.
The majority of studies conducted in recent years have focused on the morphological features of medical images. Previous studies have summarized the typical radiologic appearances of mucinous cystadenoma: located in the body or tail of pancreas and characterized by solitary cysts, mural nodules, enhancement of the peripheral wall and diameters greater than 2 cm [13, 22, 27-29]. Some researchers have concluded that the diagnosis of serous cystadenoma can be based on the lesion’s radiologic presentations, including multilobular masses, central calcifications and lack of wall enhancement [13, 22]. However, the results have been controversial in different researches. Johnson et al have reported that blind reviewers are able to correctly classify above 90% of cases of mucinous or serous cystadenomas, whereas Curry et al have reported that the rates of reviewers correctly identified serous cystadenoma and mucinous cystadenoma are 27% and 25%, respectively [12, 29]. In this study, we also assessed the performance of morphological features in the differentiation diagnosis of pancreatic serous and mucinous cystadenomas and suggested that tumor location, size and lobulated contour were reliable indices. Moreover, the combination use of location, size, wall enhancement, mural nodule, solitary cyst, central calcification and lobulated contour could improve the diagnostic value.
Texture analysis refers to a variety of mathematical methods that could be used to describe the position and intensity of signal features, which provides a useful way to maximize the information that can be derived from medical images[14]. Many studies focused on textural features have been performed. It has been proposed that textural parameters extracted from the disease lesions can be used to discriminate benign and malignant breast tumors, benign and malignant thyroid nodules, pancreatic lymphoma and pancreatic adenocarcinoma, as well as primary and metastatic lung lesions [15, 16, 30, 31]. However, less attention is being paid to textural features of pancreatic cystadenomas, which may be helpful in discrimination of serous and mucinous cystadenomas. In the present study, the results demonstrated that textural parameters were relative good indices in the differentiation of serous and mucinous cystadenomas. Furthermore, the combination of morphological and texture analysis can significantly improve the diagnostic performance. As an AUC > 0.8 indicated a good accuracy, this combination is considered to be able to distinguish between pancreatic mucinous cystadenoma and serous cystadenoma, and it has potential clinical practical value [18].
There are several limitations in this study. Firstly, the number of patients is relatively small. Second, this is a retrospective analysis in a single center. Third, there is subjectivity in the process of manually outlining the lesion boundary. Therefore, prospective studies with a large population are required to confirm the validity of the present findings.