Differentiating Between Pancreatic Adenosquamous Carcinoma and Pancreatic Ductal Adenocarcinoma Using Computed Tomography.

PURPOSE: To identify CT features that may help discriminate between pancreatic adenosquamous carcinoma (PASC) and pancreatic ductal adenocarcinoma (PDAC).

METHODS

CT examinations of 42 patients with PASC were analyzed by 2 independent readers and compared to those obtained in 42 patients with PDAC. Sensitivity, specificity, and accuracy of each variable for diagnosing PASC versus PDAC were calculated. Associations between variables and PASC were examined using univariable and multivariable analyses. A CT signature was developed to distinguish PASC from PDAC.

RESULTS

PASC presented as single (100%), oval (93%), and heterogeneously enhancing (98%) pancreatic mass with a mean largest diameter of 46.2 ± 18.5 mm, vessel encasement (69%), and segmental portal hypertension (64%), in association with hepatic metastases (52%). In univariable analysis, ring enhancement (odds ratio [OR], 25.23; P = .002), internal necrosis (OR, 9.48; P < .001), heterogeneous tumour enhancement (OR, 25.23; P = .002), and segmental portal hypertension (OR, 4.5; P = .001), were the most discriminating CT findings for the diagnosis of PASC. In multivariable analysis, internal necrosis (adjusted OR, 5.44; 95% confidence interval [CI]: 1.83-17.34; P = .003), heterogeneous tumour enhancement (adjusted OR, 8.80; 95% CI: 1.41-171.47; P = .049), and segmental portal hypertension (adjusted OR, 2.96; 95% CI: 1.02-8.97; P = .048), were independent variables strongly associated with the diagnosis of PASC. The CT signature yielded 81% sensitivity (95% CI: 66-91), 74% specificity (95% CI: 58-86), and area under the receiver operating characteristic curve of 0.840 (95% CI: 0.756-0.924) for diagnosing PASC.

CONCLUSION

CT examination demonstrates several features that help discriminate between PASC and PDAC. A CT signature based on 3 imaging features can help distinguish PASC from PDAC.