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.

[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.

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.

[Diffusion-weighted MR imaging of liver pathology: principles and clinical applications]. / Imagerie par résonance magnétique de diffusion (IRMD) en pathologie hépatique: principe et applications cliniques.

Due to ongoing technological advances, the range of clinical applications for diffusion-weighted MR imaging has expanded to now include abdominal pathology. Current applications for liver pathology include two main directions. First, oncologic imaging with detection, characterization and follow-up of lesions. Second, evaluation of diffuse liver diseases, including hepatic fibrosis. The diagnostic impact and role of diffusion-weighted MR imaging remain under investigation, but appear promising. Because of its short acquisition time, sensitivity, and additional information it provides, diffusion-weighted MR imaging should be included in routine liver imaging protocols.

[Postoperative imaging after colorectal surgery]. / Imagerie post-opératoire de la chirurgie colorectale.

Surgery for the treatment of colorectal diseases has been evolving rapidly recently. In addition to classical surgical procedures (colectomy, abdominoperineal resection), new surgical procedures include coloproctectomy with creation of an ileoanal anastomosis and ileal pouch, pelvic reconstructions (omentoplasty, placement of myocutaneous flaps) and creation of different colic anastomoses after anterior rectal resection. Even if computed tomography and fluoroscopic contrast examinations are still commonly used to assess postoperative changes and complications, especially infections, pelvic magnetic resonance imaging is useful to depict postoperative changes, detect complications such as fistulas and tumor recurrence in patients who have undergone surgery for primary or recurrent rectal disease. The main surgical techniques, their respective indications and postsurgical imaging features will be discussed. The main complications and imaging work-up will also be reviewed.

Phenotypic expression of ferroportin disease in a family with the N144H mutation.

Ferroportin is a putative transmembrane channel involved in the exit of iron out of the enterocytes, the macrophages and the hepatocytes. Mutations in the human gene coding ferroportin have been linked to an unusual form of iron overload, now referred to as "hemochromatosis type IV" or "ferroportin disease" characterized by a prevalent iron overload of macrophages and liver Küpffer cells. We report four patients from a same family with ferroportin disease associated with the N144H mutation. We show that in this family the mutation which is fully penetrant, may act through an increased iron export from macrophages as suggested by the unexpected absence of iron overload in the spleen and bone marrow detected by magnetic resonance imaging, that it co-segregates with a phenotype close to the classical form of HFE-associated hemochromatosis and was associated, in the oldest patient, with the development of hepatocellular carcinoma in a non cirrhotic liver. Our findings illustrate the existence of a genotype-phenotype relationship in "ferroportin disease", suggest that MRI may be useful in determining this phenotype and show that hepatocellular carcinoma may occur in these patients even without cirrhosis. This observation justifies careful follow-up of this subgroup of patients.

[Imaging of incidental cystic lesions of the pancreas]. / Imagerie des lésions kystiques du pancréas de découverte fortuite.

Cystic lesions of the pancreas, with an estimated prevalence of 20%, frequently are incidental findings at imaging on asymptomatic patients. Pseudocysts, typically in a setting of pancreatitis, should first be excluded. Characterization of cystic tumors is more complicated. Still, it is important to differentiate between benign and malignant lesions. Multi-detector row CT and MRI allow characterization of such lesions in over 75% of cases. Indeterminate lesions should undergo endoscopic US with biopsy/aspiration and fluid analysis, especially for mucin producing tumors (rounded with thick enhancing wall). When imaging fails to fully characterize a lesion, follow-up may be proposed for lesions less than 3 cm in size, that are either unilocular with thin nonenhancing wall (simple cyst) or lobulated multilocular with thin nonenhancing wall (serous cystadenoma, isolated side branch IPMTP). Follow-up imaging shows that these tumors usually show very little change over time. Management is based on comparing estimated patient survival without treatment to surgical risks (morbidity, mortality, functional sequelae from the procedure).

[Imaging of thoracic pathology in patients with AIDS]. / Imagerie des pathologies thoraciques chez le patient VIH au stade sida.

The imaging features of infectious and non-infectious pathologies in HIV patients with AIDS (less than 200 CD4/mm3) are illustrated. Opportunistic infections, tumors and vascular pathologies have variable appearances based on the degree of immunosuppression and patient compliance with opportunistic infection prophylaxis. Because of advances in retroviral treatments and wider use of anti-infectious prophylaxis, thoracic pathologies in AIDS patients are less frequent but must nonetheless be recognized, and diagnosis should be suggested in patients with unknown serologic status.

[Solitary fibrous tumor of the liver]. / Tumeur fibreuse solitaire du foie.

Solitary fibrous tumor (SFT) is commonly found on serosal surfaces, and is rarely localized in the liver. There are benign and malignant variants of hepatic SFT. We report a new case of benign SFT. Our patient, a 63-year old woman, who has been followed for 5 years for an asymptomatic liver mass, was admitted for abdominal pain. Ultrasonography (US), CT, MR Imaging and angiography showed the liver mass with typical imaging features, situated in the right hepatic lobe with blood supply from the hepatic artery. Histopathological examination demonstrated a highly vascularized tumor, composed of short spindle cells alternating with hypocellular collagenous regions, with a hemangiopericytoma-like vascular pattern. The immunohistochemical staining was positive for CD 34. Tumor resection was performed. Follow-up 8 years after the resection showed no tumor recurrence or metastasis, thus confirming the initial diagnosis of benign SFT.