Epithelioid glioblastoma is among the rarest variants of glioblastoma and is not formally recognized in the World Health Organization classification; it is composed of monotonous, discohesive sheets of small, round cells with eccentric nuclei and eosinophilic cytoplasm devoid of cytoplasmic stellate processes, showing the retention of nuclear staining of INI-1 protein. Here, we report a case involving a 22-year-old man with a right occipital lobe tumor, which comprised mainly epithelioid tumor cells with a small area of diffusely infiltrating less atypical astrocytoma cells showing a lower cell density. Array comparative genomic hybridization separately performed for each histologically distinct component demonstrated eight shared copy number alterations (CNAs) and three CNAs observed only in epithelioid cells; one of the latter was a homozygous deletion of a tumor suppressor gene, LSAMP, at 3q13.31. BRAF V600E mutation was observed both in epithelioid tumor cells and in diffusely infiltrating less atypical astrocytoma cells. Our findings suggest that the regional loss of LSAMP led to the aggressive nature of epithelioid cells in the present case of epithelioid glioblastoma.

Recently, it was reported that ependymoblastoma and embryonal tumor with abundant neuropil and true rosettes (ETANTR) show 19q13.42 amplification at a high frequency, suggesting that these tumors may constitute a single entity. As ependymoblastic rosettes are the most prominent features in both subtypes, embryonal tumor with multilayered rosettes (ETMR) was proposed, for which 19q13.42 amplification represents a specific molecular hallmark. However, ependymoblastic rosettes are not specific to ependymoblastoma and ETANTR, and are also found in a few other embryonal tumors as well as immature teratomas, and knowledge on 19q13.42 amplification in these tumors is limited. In this study, we performed fluorescence in situ hybridazation (FISH) analysis and differential polymerase chain reaction (PCR), and detected 19q13.42 amplification in three out of four ETANTR, one ependymoblastoma and one medulloepithelioma with ETANTR components, whereas none of the two atypical teratoid/rhabdoid tumors (AT/RT) with ependymoblastic rosettes nor two immature teratomas with developing neuroectodermal structures showed such amplification, suggesting that medulloepitheliomas would possibly be included in ETMR, and ependymoblastic rosettes in AT/RT do not signify that these tumors constitute ETMR. Also, we found C19MC rather than miR-371-373 was amplified in one ETANTR, suggesting that C19MC miRNA cluster seems to be more closely linked to the pathogenesis of ETMR.

Atypical teratoid/rhabdoid tumors (AT/RT) are rare, aggressive, embryonal brain tumors that occur most frequently in very young children; they are characterized by rhabdoid cells and loss of INI1 protein nuclear expression. Here, we report the case of a 24-year-old man with a left frontal lobe tumor that was composed mainly of rhabdoid cells showing loss of INI1 nuclear reactivity and polyphenotypic immunohistochemical expression, with a small INI1-positive component of ependymoma. Array comparative genomic hybridization separately conducted for each histologically distinct component revealed 22 shared identical copy number alterations, including loss of heterozygosity of chromosome 22q containing the INI1 locus. Furthermore, we found the C11orf95-RELA fusion gene, the genetic hallmark of supratentorial ependymomas, not only in the ependymoma component but also in the AT/RT component by fluorescence in situ hybridization analysis, suggesting that the AT/RT cells secondarily progressed from the preexisting ependymoma cells. A second genetic inactivating event in the INI1 gene was not detected in the AT/RT component. There are several reported cases of AT/RT (or INI1-negative rhabdoid tumors) arising in the setting of other primary brain tumors (gangliogliomas, pleomorphic xanthoastrocytomas, and high-grade gliomas), but the present case

Recurrent fusion genes involving C11orf95, C11orf95-RELA, have been identified only in supratentorial ependymomas among primary CNS tumors. Here, we report hitherto histopathologically unclassifiable high-grade tumors, under the tentative label of "ependymoma-like tumors with mesenchymal differentiation (ELTMDs)," harboring C11orf95-NCOA1/2 or -RELA fusion. We examined the clinicopathological and molecular features in five cases of ELTMDs.Except for one adult case (50 years old), all cases were in children ranging from 1 to 2.5 years old. All patients presented with a mass lesion in the cerebral hemisphere. Histologically, all cases demonstrated a similar histology with a mixture of components. The major components were embryonal-appearing components forming well-delineated tumor cell nests composed of small uniform cells with high proliferative activity, and spindle-cell mesenchymal components with a low-to high-grade sarcoma-like appearance. The embryonal-appearing components exhibited minimal ependymal differentiation including a characteristic EMA positivity and tubular structures, but histologically did not fit with ependymoma because they lacked perivascular pseudorosettes, a histological hallmark of ependymoma, formed well-delineated nests, and had diffuse and strong staining for CAM5.2. Molecular analysis identified C11orf95-NCOA1, -NCOA2, and -RELA in two, one, and two cases, respectively. t-distributed 2 of 14 | TOMOMASA eT Al.

We report the case of a 24-year-old woman with systemic arterial supply to the normal basal segments of the left lower lobe of the lung. She experienced repeated episodes of hemoptysis. In this patient, the normal pulmonary arteries were absent in the affected segments. The aberrant artery arising from the descending thoracic aorta was embolized using metallic coils. The patient's recovery was uneventful, except that she had mild chest pain for 3 days after the procedure. Her symptom has not recurred since 1 year follow-up. Although proximal occlusion of the aberrant artery was observed, pulmonary infarction or necrosis of the affected segments was not shown on follow-up computed tomography. Transarterial embolization can be an alternative treatment option for patients with this rare congenital anomaly.

Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant tumors of the central nervous system that predominantly occur in infants, and are characterized by the presence of rhabdoid cells and inactivation of INI1 or (rarely) BRG1. Most AT/RT are identified as primary tumors; however, rare AT/RT or INI1-deficient RTs arising from other primary tumors have been reported. Here, we report 3 cases of hitherto unclassifiable low-grade tumors with loss of INI1 nuclear expression, for which we propose the designation of central nervous system low-grade diffusely infiltrative tumors with INI1 deficiency (CNS LGDIT-INI1), 2 of which progressed to secondary RT. All 3 CNS LGDIT-INI1 exhibited a similar histology: diffusely distributed small tumor cells with round to oval or irregular nuclei and scant cytoplasm were admixed with degenerative neurons and large reactive astrocytes in an edematous, myxoid, or collagenous background. Mitotic figures were absent. Immunohistochemistry revealed that the tumor cells in all 3 CNS LGDIT-INI1 and 2 RT were negative for INI1. Genetically, total or partial homozygous deletions of the INI1 gene were detected in all CNS LGDIT-INI1 and RT excluding 1 CNS LGDIT-INI1 without sufficient DNA quality and quantity. Despite the loss of INI1 expression, these low-grade lesions were clearly distinguishable from AT/RT by their low proliferative activity, diffusely infiltrative growth pattern, and lack of rhabdoid cells and polyphenotypic immunoreactivity. In conclusion, CNS LGDIT-INI1 may represent a rare group of tumors that are clinically indolent but have a high propensity to progress to RT.

BackgroundMeandering main pancreatic duct (MMPD), which comprises loop type and reverse-Z type main pancreatic duct (MPD), has long been discussed its relation to pancreatitis. However, no previous study has investigated its clinical significance. We aimed to determine the non-biased prevalence and the effect of MMPD on idiopathic pancreatitis using non-invasive magnetic resonance (MR) technique.Methods and FindingsA cross-sectional study performed in a tertiary referral center. The study enrolled 504 subjects from the community and 30 patients with idiopathic pancreatitis (7 acute, 13 chronic, and 10 recurrent acute). All subjects underwent MR scanning and medical examination. MMPD was diagnosed when the MPD in the head of pancreas formed two or more extrema in the horizontal direction on coronal images of MR cholangiopancreatography, making a loop or a reverse-Z shaped hairpin curves and not accompanied by other pancreatic ductal anomaly. Statistical comparison was made among groups on the rate of MMPD including loop and reverse-Z subtypes, MR findings, and clinical features. The rate of MMPD was significantly higher for all idiopathic pancreatitis/idiopathic recurrent acute pancreatitis (RAP) (20%/40%; P<0.001/0.0001; odds ratio (OR), 11.1/29.0) than in the community (2.2%) but was not higher for acute/chronic pancreatitis (14%/8%; P = 0.154/0.266). Multiple logistic regression analysis revealed MMPD to be a significant factor that induces pancreatitis/RAP (P<0.0001/0.0001; OR, 4.01/26.2). Loop/reverse-Z subtypes were found more frequently in idiopathic RAP subgroup (20%/20%; P = 0.009/0.007; OR, 20.2/24.2) than in the community (1.2%/1.0%). The other clinical and radiographic features were shown not associated with the onset of pancreatitis.ConclusionsMMPD is a common anatomical variant and might be a relevant factor to the onset of idiopathic RAP.

The CT morphology of CLM predicts tumor viability and long-term surgical outcomes after chemotherapy.