Evolution of incidental branch-duct intraductal papillary mucinous neoplasms of the pancreas: A study with magnetic resonance imaging cholangiopancreatography

Abstract

AIMTo investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms (bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography (MRCP) follow-up.METHODSWe retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs (mean 4.4) to follow-up incidental, presumed bd-IPMN without signs of malignancy, found or confirmed at a baseline MRCP examination. Median follow-up time was 48.5 mo (range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes: (1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and (2) alert findings, defined as worrisome features and/or high risk stigmata (e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.RESULTSWe found a total of 343 cysts (per-patient mean 5.1) with average size of 8.5 mm (range 5-25 mm). Imaging evolution was observed in 32/72 patients (44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts (13.7%). There was a main trend towards small (< 10 mm) increase and/or decrease of cysts size at a median time of 22.5 mo. Alert findings developed in 6/72 patients (8.3%; 95%CI: 3.4-17.9) over a wide interval of time (13-63 mo). No malignancy was found on endoscopic ultrasound with fine-needle aspiration (5/6 cases) or surgery (1/6 cases). No clinical or initial MRCP features were significantly associated with changes in bd-IPMN appearance (P > 0.01).CONCLUSIONChanges in MRCP appearance of incidental bd-IPNM were frequent over the follow-up (44.4%), with relatively rare (8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging follow-up should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.

Early Detection of Pancreatic Cancer: Opportunities and Challenges

“…[54][55][56] MRI/magnetic resonance cholangiopancreatography (MRCP), however, is considered by many as the standard modality for diagnosing a BD-IPMN, with a sensitivity of up to 88%. 53,[57][58][59][60] MRI/MRCP is superior to CT in its ability to identify MPD connectivity and features of malignancy. Furthermore, complementing MRCP with secretin stimulation can elucidate pancreatic ductal anatomy.…”

Pancreatic fat content may increase the risk of imaging progression in low‐risk branch duct intraductal papillary mucinous neoplasm

“…Several studies have reported that those factors included cystic features (cyst size, the presence of a mural nodule, MPD dilatation, and growth rate in size) and patient's factors (symptoms, diabetes mellitus, smoking, or obesity). However, few data are available on risk factors of imaging progression in low‐risk BD‐IPMN . Gausman et al concluded that an initial cyst size ≥2 cm, multifocality of cystic lesions, the patient's past history of prostate cancer, and of smoking could independently predict the onset of new worrisome features.…”

“…Gausman et al concluded that an initial cyst size ≥2 cm, multifocality of cystic lesions, the patient's past history of prostate cancer, and of smoking could independently predict the onset of new worrisome features. However, Girometti et al reported that the clinical or baseline features of images under MRCP did not predict imaging evolution or the development of alert findings. The well‐known risk factors for pancreatic cancer include IPMN as well as smoking, diabetes mellitus, a family history of pancreatic cancer and obesity .…”

“…However, few data are available on risk factors of imaging progression in low-risk BD-IPMN. 16,19 Gausman et al 16 17 Fukuda et al 25 reported that the density of fatty pancreas measured by CT had an independent association with pancreatic cancer. Very recently, we reported that pancreatic fat content determined by CT had a significant relationship with the presence of IPMN.…”

“…Patients with BD‐IPMN but without worrisome features or high‐risk stigmata who had undergone surveillance with at least one follow‐up MRI examination, irrespective of their follow‐up period, were included. The incidence of the two outcomes was assessed over the entire follow‐up period by comparing the images of the initial MRI with those of the last follow‐up MRI, in accordance with a report by Girometti et al: (a) imaging progression, defined as any increase in number, size, or appearance, including an increase in the size of the MPD and/or the occurrence of a mural nodule in ≥1 follow‐up examination; and (b) alert findings, defined as the occurrence of worrisome features and/or high‐risk stigmata. Therefore, imaging progression included cases of alert findings.…”