Magnetic Resonance Diffusion-Weighted Imaging for Detecting Fundal Intracholecystic Papillary Neoplasm inside Rokitansky-Aschoff Sinuses: A Comparison of Two Cases and a Literature Review

Round 1

Reviewer 1 Report

In the current manuscript, the authors report a case of intracolecular papillary neoplasia (ICPN) evolved in the context of gallbladder adenomyomatosis, highlighting how restriction in diffusion-weighted sequences is crucial in discriminating from adenomyomatosis devoid of neoplastic lesions. This is the first report in the literature on DWI in ICPN .

In addition, a comprehensive review of the current literature regarding ICPN in the context of Rokitansky-Aschoff sinuses and bile duct neoplasms is provided.

The work is interesting because the noninvasive diagnosis of ICPN is poorly addressed in the literature; certainly more cases are needed to strengthen this topic.

The article needs further review of the English.

Author Response

In the current manuscript, the authors report a case of intracolecular papillary neoplasia (ICPN) evolved in the context of gallbladder adenomyomatosis, highlighting how restriction in diffusion-weighted sequences is crucial in discriminating from adenomyomatosis devoid of neoplastic lesions. This is the first report in the literature on DWI in ICPN.
In addition, a comprehensive review of the current literature regarding ICPN in the context of Rokitansky-Aschoff sinuses and bile duct neoplasms is provided.
The work is interesting because the noninvasive diagnosis of ICPN is poorly addressed in the literature; certainly more cases are needed to strengthen this topic.

--Thank you for your revision, this was exactly the aim of our article. We would like to spread awareness about the noninvasive diagnosis of ICPN, especially in the complex (and rare) cases where it co-localizes with adenomyomatosis. This will hopefully encourage future research on larger cohorts to explore this peculiar diagnostic challenge.

The article needs further review of the English.

--Following your suggestion, we submitted the manuscript to our collaborator NC, a native English speaker. NC did a proof-reading of the revised manuscript and further corrected the English. In addition, he also provided feedback about the topic and helped with the additional literature research. Therefore, he is now listed among the authors in the updated version of the manuscript.

Reviewer 2 Report

This manuscript is a case report that suggested the usefulness of MR-DWI for detecting ICPN inside RAS. MRI-DWI is likely to be useful to distinguish between benign and malignant gallbladder lesions, which topic has not been well investigated yet. Therefore, this article will be of interest to clinicians in the field.

However, the following minor issues require clarification:

Minor

1. I recommend that the authors also provide histopathological macroscopic and microscopic images as ICPN within RAS is rare.
2. The authors should discuss MRI-DWI findings in adenomyomatosis with RAS by referring related literatures, which can support the authors’ conclusion.

I hope these comments will be helpful for improving this manuscript.

Author Response

This manuscript is a case report that suggested the usefulness of MR-DWI for detecting ICPN inside RAS. MRI-DWI is likely to be useful to distinguish between benign and malignant gallbladder lesions, which topic has not been well investigated yet. Therefore, this article will be of interest to clinicians in the field.

--Thank you for your revision, this was the aim of our article. We hope that this manuscript will warn radiologists to carefully consider suspicious findings (as DWI restriction) within RAS mucosa in order to successfully pose diagnosis of malignancy.

However, the following minor issues require clarification:
Minor
1. I recommend that the authors also provide histopathological macroscopic and microscopic images as ICPN within RAS is rare.
2. The authors should discuss MRI-DWI findings in adenomyomatosis with RAS by referring related literatures, which can support the authors’ conclusion.

--Thanks for raising these points. We strongly agree with your comments, and we believe that addressing them improved the manuscript:
1. Our pathologist, AV, revised the case further and provided histopathological microscopic images, that were included in the manuscript as Figure 2. We believe that this addendum was beneficial for the article, and makes the message stronger. Unfortunately, it was not possible to retrieve macroscopic images.
2. We further reviewed the literature to assess the role of Diffusion MRI in ADM/RAS. Few articles in the literature discuss DWI/ADC findings in typical benign ADM/RAS, but they rather refer to DWI as a tool for differentiating benign to malignant lesions. However, we found some relevant articles on the topic and we decided to discuss them articles at the beginning of chapter 4.2 in the Discussion section. In addition, we added a final remark at the end of 4.2 to express what DWI-MRI findings should be expected in RAS/ADM and how to discriminate RAS/ADM from malignancies.