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In 2016, the World Health Organization (WHO) central nervous system (CNS) classification scheme incorporated molecular parameters in addition to traditional microscopic features for the first time. Molecular markers add a level of objectivity that was previously missing for tumor categories heavily dependent on microscopic observation for pathologic diagnosis. This article provides a brief discussion of the major 2016 updates to the WHO CNS classification scheme and reviews typical MR imaging findings of adult primary CNS neoplasms, including diffuse infiltrating gliomas, ependymal tumors, neuronal/glioneuronal tumors, pineal gland tumors, meningiomas, nerve sheath tumors, solitary fibrous tumors, and lymphoma.

A 62-year-old female with a history of hepatitis C presented with one week of worsening abdominal distension. On physical examination, she had icterus, abdominal distension, shifting dullness, and a positive fluid wave. Computed tomography (CT) of the abdomen and pelvis demonstrated a small left hepatic lobe lesion and moderate ascites. Chest CT demonstrated a large substernal mass (3.5 × 1.7 cm) in the anterior mediastinal fat in the region of prepericardial lymph nodes. Following resection of the substernal mass, histopathology revealed metastatic involvement by poorly differentiated hepatocellular carcinoma (HCC). The patient was in fulminant liver failure postoperatively and succumbed to her disease. Mediastinal lymph nodes metastases in HCC are rare and often portend a poor prognosis when present. We discuss a case of HCC presenting with a substernal mass, and provide a literature review of the management and prognosis of lymphatic spread of HCC.

Isolated unilateral absence of the pulmonary artery (UAPA) exhibits a benign course and often goes undiagnosed until adulthood. We present a 39-year-old male admitted for left-sided congestive heart failure (CHF) exacerbation. However, chest radiograph demonstrated findings suspicious for UAPA that was ultimately confirmed on computed tomography. Because both CHF and UAPA present similarly with exercise intolerance and dyspnea, a high index of suspicion is required to secure the diagnosis, and in this case, symptoms attributed to CHF may have contributed to delay. A strong awareness of typical radiographic findings allows for initiation of confirmatory tests necessary for a correct diagnosis.

Papillary cystadenocarcinomas (PCAs) are rare low-grade salivary gland tumors first introduced in the World Health Organization classification in 1991. While classically regarded as a low-grade malignancy, PCAs with more clinically and histologically high-grade features have been reported, reflecting the often-underrecognized morphological diversity of this entity. Although no universally advocated grading system exists, high-grade PCAs tend to demonstrate locally aggressive features, cytologic atypia, high mitotic rate, necrosis, and an absence of papillary features. We present a case of a 51-year-old male with slow-onset, progressive right facial fullness over four years. Contrast-enhanced computed tomography of the neck demonstrated a 3.3 cm peripherally enhancing cystic and solid mass in the right superficial lobe of the parotid gland. Following a superficial parotidectomy and a selective right neck dissection, histopathology demonstrated a large cyst with papillary projections lined with cuboidal cells of mild to moderate atypia and surrounding solid tumor nests. The tumor displayed stromal, lymphovascular, and subcutaneous fibroadipose tissue invasion. One of 12 lymph nodes was positive for metastatic carcinoma without extranodal extension. A diagnosis of intermediate-grade PCA was rendered. This case report summarizes the features typical of high-grade PCAs, the few reported cases of intermediate- and high-grade PCAs within the existing literature and provides a brief overview of the radiological and pathological differential diagnosis when considering a parotid gland PCA.

Infratentorial lesions in patients with multiple sclerosis are associated with long-term disability. Two-dimensional fluid-attenuated inversion recovery demonstrates poor infratentorial lesion detection when compared to T2-weighted spin echo. Evidence of improved detection with 3D fluid-attenuated inversion recovery has been conflicting. This study compares the infratentorial lesion detection performance, observer performance, and signal and contrast properties between T2-weighted spin echo, 2D, and 3D fluid-attenuated inversion recovery.Two board-certified radiologists independently reviewed and counted infratentorial lesions from 85 brain MRIs in patients with clinically definite multiple sclerosis and concurrent 3D, 2D fluid-attenuated inversion recovery, and T2-weighted spin echo sequences. Contrast-to-noise and signal-to-noise ratios were measured for 25 MRIs. Wilcoxon signed-rank test was used for pairwise comparisons of the combined average infratentorial lesion count, contrast-to-noise, and signal-to-noise ratios, and was adjusted for three pairwise comparisons using Bonferroni correction. A corrected p value 0.05 was considered statistically significant.The number of lesions on 3D fluid-attenuated inversion recovery was significantly higher than those on 2D (p 0.001) and T2-weighted spin echo (p 0.001). Results of contrast-to-noise and signal-to-noise ratios were overall mixed and predominantly not concordant with lesion count findings, with T2-weighted spin echo demonstrating the highest signal-to-noise ratios and contrast-to-noise ratio of lesion compared with white matter but the lowest contrast-to-noise ratio of lesion compared with gray matter.The 3D fluid-attenuated inversion recovery sequence addresses the disadvantage of poor infratentorial lesion detection on 2D, while still maintaining the advantage over T2-weighted spin echo in the detection of lesions adjacent to the cerebrospinal fluid.

Cases of e-cigarette or vaping product use-associated lung injury (EVALI) have rapidly reached epidemic proportions, yet there remain limited reports within the literature on the associated imaging findings. We describe the most common imaging findings observed on chest computed tomography (CT) and chest radiograph (CXR) at presentation and at short-term follow-up at our major pediatric hospital. A retrospective review of the electronic medical records was performed on all patients with suspected EVALI who were treated at a major pediatric hospital and 11 patients were included for analysis. Two board-certified pediatric radiologists then categorized the CXRs as either normal or abnormal, and further performed a systematic review of the chest CTs for imaging findings in the lungs, pleura and mediastinum. Interrater discordance was reconciled by consensus review. The 11 patients (9 males:2 females) ranged in age from 14 to 18 years. Gastrointestinal and constitutional symptoms were present in all patients, whereas shortness of breath and cough were reported in 5/11 and 6/11 patients, respectively. The CXR was abnormal in 10/11 patients, whereas all chest CTs were abnormal. The most common CT findings included consolidation, ground-glass opacities, interlobular septal thickening, lymphadenopathy and crazy-paving pattern. Almost all patients demonstrated subpleural sparing, and less than half also demonstrated peribronchovascular sparing. There was complete or near-complete resolution of imaging abnormalities in 5/6 patients with a median follow-up duration of 114 days. Pulmonary opacities with subpleural and peribronchovascular sparing was a commonly observed pattern of EVALI in the pediatric population at this institution. A CXR may not be sufficiently sensitive in diagnosing EVALI, and radiologists and clinicians should exercise caution when excluding EVALI based on the lack of a pulmonary opacity. Caution should also be exercised when excluding EVALI solely based on the lack of respiratory symptoms. Despite extensive pulmonary involvement at presentation, findings may resolve on short-term follow-up imaging.

Branchial cleft cysts are the most common lesions in the lateral neck with ectopic thyroid tissue found only rarely within these cysts. Over the years, multiple cases of papillary thyroid carcinoma arising from these ectopic thyroid tissues have been described in the literature with these cases sharing a normal thyroid gland on surgical and histological evaluation. Recently, however, there are three cases of papillary thyroid carcinoma in a branchial cleft cyst reported to be the result of metastasis from a thyroid primary. We present a 49-year-old female with a rare case of papillary thyroid carcinoma metastasis to a branchial cleft cyst with imaging characteristics that may prospectively suggest metastatic involvement.

BACKGROUND AND PURPOSE Perform an investigation of the frequency and distribution of leptomeningeal enhancement on postgadolinium magnetization-prepared FLAIR (MPFLAIR) in multiple sclerosis (MS) on 7 Tesla (7T) MRI and to relate this finding to measures of brain structure and lesion volumes. METHODS Twenty-nine participants with MS underwent 7T MRI of the brain. Three healthy volunteers (HVs) were scanned for comparison. Areas of postcontrast leptomeningeal enhancement were identified. Images were segmented for brain structure and lesion volumes. The relationship between leptomeningeal enhancement and clinical and volumetric data was explored. RESULTS Two patterns of enhancement were found: “nodular” (discrete, spherical nodules at the pial surface or subarachnoid space) and “spread/fill” (appearance of contrast spread through the local subarachnoid space). Twenty-six of 29 (90%) MS participants had at least one focus of leptomeningeal enhancement. Nodular foci were present in 15 of 29 (51%) MS participants. Spread/fill foci were present in 22 of 29 (76%) MS participants. Two HVs had examples of nodular foci, but none had spread/fill enhancement. MS participants with spread/fill foci were older (48.9 years [SD 8.3]) than those without (33.3 years [SD 11.5], P = .005). MS participants with spread/fill foci had reduced cortical gray matter volume compared to those without (P = .020). CONCLUSIONS Leptomeningeal enhancement on postcontrast 7T MPFLAIR is more prevalent than prior reports at 3T—occurring at frequencies closer to histopathologic data. Spread/fill foci are associated with reduced cortical gray matter volumes and may represent blood-meningeal barrier breakdown near sites of meningeal inflammation, whereas nodular foci may be a normal variant.

BACKGROUND AND PURPOSE: Neuromyelitis optica spectrum disorders are inflammatory demyelinating disorders with optic neuritis and/or longitudinally extensive transverse myelitis episodes. We now know that neuromyelitis optica spectrum disorders are associated with antibodies to aquaporin-4, which are highly concentrated on astrocytic end-feet at the blood-brain barrier. Immune-mediated disruption of the blood-brain barrier may manifest as contrast enhancement on brain MR imaging. We aimed to delineate the extent and frequency of contrast enhancement on brain MR imaging within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and to correlate contrast enhancement with outcome measures. MATERIALS AND METHODS: Brain MRIs of patients with neuromyelitis optica spectrum disorders were evaluated for patterns of contrast enhancement (periependymal, cloudlike, leptomeningeal, and so forth). The Fisher exact test was used to evaluate differences between the proportion of contrast enhancement in patients who were seropositive and seronegative for aquaporin-4 antibodies. The Mann-Whitney test was used to compare the annualized relapse rate and disease duration between patients with and without contrast enhancement and with and without seropositivity. RESULTS: Brain MRIs of 77 patients were evaluated; 59 patients (10 males, 49 females) were scanned within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and were included in the analysis. Forty-eight patients were seropositive, 9 were seronegative, and 2 were not tested for aquaporin-4 antibodies. Having brain contrast enhancement of any type during an acute attack was significantly associated with higher annualized relapse rates (P = .03) and marginally associated with shorter disease duration (P = .05). Having periependymal contrast enhancement was significantly associated with higher annualized relapse rates (P = .03). CONCLUSIONS: Brain MRIs of patients with neuromyelitis optica spectrum disorders with contrast enhancement during an acute relapse of optic neuritis and/or longitudinally extensive transverse myelitis are associated with increased annual relapse rates.

Solitary fibrous tumors are rare spindle cell tumors of mesenchymal origin most commonly found in the pleura and peritoneum. In contrast, extra-serosal locations are rare. We present a 41-year-old female with a progressively enlarging left-sided neck mass of one-year duration with subsequent rapid-onset growth over two months, and was pathologically confirmed to be a benign solitary fibrous tumor of the thyroid gland.

Fingolimod is an oral medication approved by the Food and Drug Administration in 2009 for the treatment of relapsing remitting multiple sclerosis (RRMS). Initial clinical trials did not show a significantly increased rate of serious infections with fingolimod therapy. However, a mildly increased risk of less serious infections, such as varicella zoster virus and herpes simplex virus, was reported. Recently, however, several instances of serious opportunistic infections have been reported. In the years following approval of fingolimod for use in multiple sclerosis (MS), seven cases of cryptococcal meningitis in patients undergoing treatment have been described in the literature. We present a 40-year old woman with RRMS on fingolimod therapy presenting with a rare case of cryptococcal meningitis exhibiting alterations of consciousness, which was initially diagnosed as an MS relapse.

Large septic pulmonary embolus is a rare finding in right-sided endocarditis. The entity represents a challenging diagnosis due to its variable and nonspecific clinical and radiological presentation and similarities with other conditions. We present a case of a 41 year-old woman who developed a large main pulmonary artery embolus and bilateral cavitary lung nodules in the setting of severe sepsis. Pulmonary artery exploration and clot retrieval ultimately revealed a large septic embolus from Streptococcus mutans native pulmonary valve endocarditis. The diagnosis of septic pulmonary emboli from right-sided endocarditis should be considered in patients with ancillary findings of septic embolic phenomenon, particularly the presence of multifocal cavitary nodules and in the setting of appropriate predisposing factors.

A 28-year-old man recently diagnosed with HIV (CD4 19 cells/mm(3), viral load 3.6 million copies/mL, not on highly active antiretroviral therapy on initial diagnosis at outside hospital), disseminated histoplasmosis, shingles and syphilis presented with paraplegia developing over 3 days. Spine MRI demonstrated a longitudinally extensive cord lesion extending from C3 to the tip of the conus. Brain MRI was consistent with meningoencephalitis. Cerebrospinal fluid findings were notable for positive varicella zoster virus (VZV) and cytomegalovirus (CMV) PCRs as well as a Venereal Disease Research Laboratory titre of 1:2. Patient was started on treatment for VZV and CMV meningoencephalitis, neurosyphilis and high-dose steroids for infectious myelitis. Repeat spine MRI demonstrated subacute intramedullary haemorrhage of the cervical cord. He was ultimately discharged to a skilled nursing facility for long-term intravenous antiviral therapy and rehabilitation. After 59 days in the hospital, his neurological exam remained grossly unchanged, with flaccid paraplegia and lack of sensation to fine touch in his lower extremities.

OBJECTIVEOligodendroglioma is a rare primary CNS neoplasm in the pediatric population, and only a limited number of studies in the literature have characterized this entity. Existing studies are limited by small sample sizes and discrepant interstudy findings in identified prognostic factors. In the present study, the authors aimed to increase the statistical power in evaluating for potential prognostic factors of pediatric oligodendrogliomas and sought to reconcile the discrepant findings present among existing studies by performing an individual-patient-data (IPD) meta-analysis and using multiple imputation to address data not directly available from existing studies.METHODSA systematic search was performed, and all studies found to be related to pediatric oligodendrogliomas and associated outcomes were screened for inclusion. Each study was searched for specific demographic and clinical characteristics of each patient and the duration of event-free survival (EFS) and overall survival (OS). Given that certain demographic and clinical information of each patient was not available within all studies, a multivariable imputation via chained equations model was used to impute missing data after the mechanism of missing data was determined. The primary end points of interest were hazard ratios for EFS and OS, as calculated by the Cox proportional-hazards model. Both univariate and multivariate analyses were performed. The multivariate model was adjusted for age, sex, tumor grade, mixed pathologies, extent of resection, chemotherapy, radiation therapy, tumor location, and initial presentation. A p value of less than 0.05 was considered statistically significant.RESULTSA systematic search identified 24 studies with both time-to-event and IPD characteristics available, and a total of 237 individual cases were available for analysis. A median of 19.4% of the values among clinical, demographic, and outcome variables in the compiled 237 cases were missing. Multivariate Cox regression analysis revealed subtotal resection (p = 0.007 [EFS] and 0.043 [OS]), initial presentation of headache (p = 0.006 [EFS] and 0.004 [OS]), mixed pathologies (p = 0.005 [EFS] and 0.049 [OS]), and location of the tumor in the parietal lobe (p = 0.044 [EFS] and 0.030 [OS]) to be significant predictors of tumor progression or recurrence and death.CONCLUSIONSThe use of IPD meta-analysis provides a valuable means for increasing statistical power in investigations of disease entities with a very low incidence. Missing data are common in research, and multiple imputation is a flexible and valid approach for addressing this issue, when it is used conscientiously. Undergoing subtotal resection, having a parietal tumor, having tumors with mixed pathologies, and suffering headaches at the time of diagnosis portended a poorer prognosis in pediatric patients with oligodendroglioma.

Liposarcoma (LPS) is a malignancy of fat and one of the most common soft tissue sarcomas. There are three major subtypes of LPS: Well-differentiated / dedifferentiated, myxoid, and pleomorphic. We review the imaging features of LPS in the abdomen and extremities, describe features that help differentiate the subtypes, and provides alternative considerations for fat-containing lesions (many benign) that can mimic LPS.

Neuromyelitis optica is a neurotropic autoimmune inflammatory disease of the central nervous system traditionally thought to exclusively involve the optic nerves and spinal cord. With the discovery of the disease-specific aquaporin-4 antibody and the increasing recognition of clinical and characteristic imaging patterns of brain involvement in what is now termed neuromyelitis optica spectrum disorder (NMOSD), MRI now plays a greater role in diagnosis of NMOSD based on the 2015 consensus criteria and in distinguishing it from other inflammatory disorders, particularly multiple sclerosis (MS). Several brain lesion patterns are highly suggestive of NMOSD, whereas others may serve as red flags. Specifically, long corticospinal lesions, hemispheric cerebral white matter lesions and periependymal lesions in the diencephalon, dorsal brainstem and white matter adjacent to lateral ventricles are typical of NMOSD. In contrast, juxtacortical, cortical, or lesions perpendicularly oriented to the surface of the lateral ventricle suggests MS as the diagnosis. Ultimately, a strong recognition of the spectrum of MRI brain findings in NMOSD is essential for accurate diagnosis, and particularly in differentiating from MS. This pictorial review highlights the spectrum of characteristic brain lesion patterns that may be seen in NMOSD and further delineates findings that may help distinguish it from MS.