Performances of preoperative CT scan to predict the pTN stage for MSI/dMMR localized colon cancers.

BACKGROUND: Neoadjuvant immunotherapy emerges as a promising strategy for patients with localized colon cancer (CC) harboring microsatellite instability/mismatch repair deficiency (MSI/dMMR). The aim of this study is to evaluate the concordance between clinical cTN stage assessed by preoperative computed tomography (CT) scan and pTN stage of MSI/dMMR CC. PATIENTS AND METHODS: Consecutive patients diagnosed for localized MSI/dMMR CC and treated with upfront surgery between 2013 and 2022 in two French centers were eligible. Two independent radiologists, blinded to pathological findings, reviewed all preoperative CT scans and assessed cTN stage, with a third radiologist reviewing discordant cases. Radiological predictive diagnostic accuracy for pT4 and pN+ (N+ = N1 or N2) were calculated. RESULTS: One hundred and thirteen patients were included (right CCs = 79%). CT scan diagnostic performances for pT4 were sensitivity (Se) = 33.3%; specificity (Sp) = 94.0%; positive predictive value (PPV) = 66.7%; and negative predictive value (NPV) = 79.6% and for pN+ were Se = 70.3%; Sp = 59.2%; PPV = 45.6%; and NPV = 80.4%. When pT-pN were combined, 37.5% of tumors identified as cT4 and/or cN+ were actually pT1-3 and pN0, and 23.1% of the pT4 and pN+ population was not identified as such radiologically. CONCLUSION: The ability of preoperative CT scan to predict pT and pN stages is limited for localized MSI/dMMR CCs. Reassessing neoadjuvant strategies' benefit-risk balance in this population is needed.

[Vasculitis of the hepatic artery: A case of a single-organ vasculitis]. / Vascularite de l'artère hépatique : à propos d'un cas d'atteinte d'organe isolée.

INTRODUCTION: Vasculitis usually have a systemic involvement. Rare cases of localized vasculitis have been described, but the exclusive involvement of the hepatic artery is exceptional. We report the case of a patient who developed a vasculitis of the right and left hepatic arteries. CASE REPORT: A 63-year-old woman presented with unexplained abdominal pain. A computed tomography of the abdomen was suggestive of vasculitis of the hepatic arteries, showing a sequence of stenosis and aneurysmal dilatations of the hepatic arteries. There were no other arterial involvement, in particular of the abdomen and the brain. No other systemic disease or infection was found. The outcome was favorable, with corticosteroids alone. DISCUSSION: The exclusive involvement of the hepatic artery is an exceptional form of localized vasculitis, with only one other case reported. This diagnosis could therefore be discussed, in the presence of unexplained hepatic hematoma or pain.

[Chyluria with "nephrotic syndrome-like" presentation: Diagnostic and therapeutic approach]. / Chylurie révélée par un « pseudo-syndrome néphrotique ¼ : démarche diagnostique et thérapeutique.

Chyluria implies an abnormal communication between the lymphatic system and the urinary tract. It is more frequent in endemic areas of lymphatic filariasis, which constitutes the main cause. Chyluria may mimic a nephrotic syndrome. Diagnosis of chyluria is based on urinary cytological and biocheminal analysis. Localization of the fistula needs medical imaging: cystoscopy, retrograde pyelography, lymphoscintigraphy and more recently magnetic resonance lymphography. Due to frequent spontaneous remissions, traitement can require only dietary measures. In case of malnutrition or clinical complications, sclerotherapy should be rapidly undertaken, before considering surgery of renal lymphatic disconnection.

MRI of cholangitis: traps and tips.

There are many limitations to the examination of the bile ducts by magnetic resonance imaging, which may be four orders: (1) technical, requiring analysis of Maximum Intensity Projection (MIP) three-dimensional (3D) volume reconstructions as well as native images, the use of T1-weighted sequences obtained in 3D to avoid entry slice phenomena, and knowledge of the inherent limits of the method, the spatial resolution of which is still less than optimal; (2) anatomical: you need to know the appearance of flow artefacts within the bile ducts and the traps that the presence of air or bleeding into the bile ducts can create; you also need to know the characteristic appearance of the indentation caused by the hepatic artery on the bile ducts and the variants and modifications seen in cases of portal biliopathy; (3) semiological: the terms used to describe bile duct abnormalities seen in MRI are often derived from imprecise descriptions used in retrograde cholangiography: irregularities of the bile ducts, a beaded 'string of pearls' appearance, a 'dead tree' appearance; (4) related to a complex disease, cholangitis which is a complex pathological condition, with possible overlaps between different conditions, such as primary sclerosing cholangitis (PSC), secondary sclerosing cholangitis, autoimmune cholangitis. In any case, the diagnosis of cholangiocarcinoma associated with PSC is always difficult. These limitations can be circumvented by using a precise exploration technique comprised of 3D magnetic resonance cholangiography sequences, which allow volume analysis, examination of native slices and of thick or thin MIP reconstructions, and heavily T2-weighted and T1-weighted 3D sequences with and without gadolinium injection, which is not always essential. The examination must be interpreted according to a stereotyped plan that includes (1) examination of the bile ducts, searching for and describing any stenosis, the presence or absence of dilatation, (2) a systematic search for any intrahepatic calculus, (3) examination of the heterogeneity of the liver parenchyma, investigation to find any liver dysmorphia and signs of portal hypertension, (4) analysis of the enhancement of the liver parenchyma and any enhancement of the wall of the bile ducts.

[Chest magnetic resonance lymphography]. / Lymphographie par résonance magnétique thoracique.

Lymphangio-MRI is a non-invasive technique that allows the precise imaging of thoracic lymphatic vessels without contrast-enhancing agents. This technique is still in progress, and will benefit from better knowledge of thoracic lymphatic diseases and further improvement of MRI spatial resolution.

MR Imaging of sclerosing cholangitis.

MRCP is a non-invasive cholangiographic technique used in detection and characterization of bile ducts abnormalities. MRCP features of primary sclerosing cholangitis are randomly distributed annular strictures alternating with slightly dilated bile ducts. Secondary sclerosing processes including ascending, ischemic, caustic, AIDS-related, eosinophilic and autoimmune cholangitis can mimic PSC at MRCP.

Hereditary intraductal papillary mucinous neoplasm of the pancreas.

Intraductal papillary mucinous neoplasm (IPMN) is a rare pancreatic tumor defined as intraductal mucin-producting neoplasm with tall, columnar, mucin-containing epithelium. IPMN have already been described in association with inherited genetic disorder including familial adenomatous polyposis and Peutz-Jeghers syndrome. However, there is no reported description of familial history of IPMN. We reported in this case-report IPMN in the first-degree relatives without familial history of colorectal polyposis or previous extra-pancreatic cancer. The rarety of IPMN suggests that the coexistence of this tumor in two first-degree relatives is probably due to a genetic inherited factor that remains to be elucidated.