• CT sign
• enhancement behaviour
• IPMN

Background. Management of branch duct type IPMNs (BD-IPMNs) largely relies on imaging finding. In particular Sendai guidelines propose surgical treatment in symptomatic BD- IPMNs or asymptomatic lesions with a diameter >3cm, in presence of mural nodules or Wirsung caliber >6mm. The International Consensus guidelines published in 2012 still suggest a conservative approach, even for lesion larger than 3cm, without other imaging findings of malignancy, removing the recommendation for surgical resection based on size alone. However, these indications have been strongly challenged by recent studies showing that small BD-IPMNs could be associated with malignancy; moreover surgical BD-IPMN treatment is confined to lesions evolved to invasive cancer, losing the possibility of a preventive therapeutic approach, especially in younger patients (<65 years). Our study aims to recognize CT signs predictive of evolution to malignancy in BD-IPMN.
Our study aims to recognize CT signs predictive of evolution to malignancy in BD-IPMN.
Methods and materials. We included 43 patients affected by BD-IPMN. For each patient we evaluated the first and the last CT exams performed in the follow-up (mean follow-up period: 37months, range: 18 months-7 years). Post-contrastographic CT study included the pancreatic (35”), venous (70”) and late (180”) phases. The following CT parameters were examined: localization, morfology (unilocular/multilocular), Wirsung caliber, baseline attenuation, parietal and septal enhancement, neural plexus (celiac and AMS) and celiac ganglia involvement, size of the main cystic lesion.
Results. In 26 patients no significant changes in CT findings were found (confirmed by imaging follow-up). Other 17 were submitted to surgical resection because of clinical symptoms or CT signs suggestive for malignant degeneration, that was confirmed at pathology in 16 cases (10/16 with a diameter <3cm). Malignancy was statistically related to baseline attenuation (p<0.0001), enhancement behaviour (<0,0001), Wirsung caliber >5mm (p<0,0001), perineural plexus and celiac ganglia involvement (p<0,0001). No correlation was found considering lesion dimension (p=0.4644).
Conclusions. Even if current guidelines propose follow-up in asymptomatic BD-IPMNs less than 3cm (or 4cm) in diameter, the event of malignant degeneration in small lesion has been described, suggesting the need of considering further imaging parameters predictive of malignancy.