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Various splenic inflammatory pseudotumours are reported to be infected with Epstein-Barr virus (EBV), which is thought to be associated with the pathogenesis of the lesion. The term ''inflammatory pseudotumour (IPT)-like follicular dendritic cell tumour'', all cases of which are also EBV positive, has recently been proposed. Here, we describe the imaging findings of these splenic tumours and present the cases of an IPTlike follicular dendritic cell tumour and two EBV-positive inflammatory pseudotumours in two female patients and one male patient. These splenic lesions were found incidentally on pre-operative or post-operative screening or at medical check-up. CT performed on all three patients revealed low-density solitary masses in the spleen. MRI was performed on one patient; the solitary mass demonstrated isointensity on T1 weighted images and low intensity on T2 weighted images relative to the surrounding splenic parenchyma. Dynamic MRI study revealed that the mass did not enhance on the early phase but enhanced to the same degree as the surrounding splenic parenchyma on the delayed phase. The imaging findings are almost identical to those found in conventional IPT because the morphology is similar in both cases; however, attention should be paid to this new entity in the diagnosis of splenic lesions because of its neoplastic nature. Longer follow-up is also necessary for these patients compared with those with conventional IPT. [ABSTRACT FROM AUTHOR]

Epstein-Barr virus (EBV) prevails among more than 90% of the adult population worldwide. Most primary infections occur during young childhood and cause no or only nonspecific symptoms; then the virus becomes latent and resides in lymphocytes in the peripheral blood. Inactive latent EBV usually causes no serious consequences, but once it becomes active it can cause a wide spectrum of malignancies: epithelial tumors such as nasopharyngeal and gastric carcinomas; mesenchymal tumors such as follicular dendritic cell tumor/sarcoma; and lymphoid malignancies such as Burkitt lymphoma, lymphomatoid granulomatosis, pyothorax-associated lymphoma, immunodeficiency-associated lymphoproliferative disorders, extranodal natural killer (NK) cell/T-cell lymphoma, and Hodgkin's lymphoma. The purpose of this article is to describe the spectrum of EBV-related diseases and their key imaging findings. EBV-related lymphoproliferative disorders and lymphomas are especially common in immunocompromised patients. Awareness of their clinical settings and imaging spectrum contributes to early detection and early treatment of possibly life-threatening disorders. [ABSTRACT FROM AUTHOR]

We have investigated the 45 GHz microwave response from an organic superconductor λ-(BEDT-TSF)2GaCl4 with Tc=4.8 K. In the superconducting state, the London penetration depth saturates well below Tc, which may provide an evidence for a conventional s-wave paring. In the metallic state, σ deviates downward from σ, while σ, which should be zero in a conventional metallic state, increases exponentially toward Tc. This anomalous metallic state has been discussed in terms of a possible formation of incoherent electron pairs in so-called a pseudogap state. [ABSTRACT FROM AUTHOR]

We have measured the specific heat on λ-(BEDT-TSF)2FeCl4 as a function of temperature by a thermal relaxation method to study the metal-to-insulator (MI) transition around 8 K and anomalous ferroelectric-like state revealed by microwave measurements for the metallic state. The specific heat exhibits a sharp peak due to the antiferromagnetic ordering at TMI=8.3 K. We have found a remarkable jump at 70 K labeled as TFM. Together with the ferroelectric-like response emerging around TFM, this result confirms thermodynamically a ferroelectric-like transition at TFM in the metallic states. Furthermore, the thermal conductance of the sample may exhibit an anomaly at TFM. [Copyright &y& Elsevier]

Using a capacitance bridge with a phase sensitive detection at frequencies f (=ω/2π)=101 to 105 Hz, we have measured the complex dielectric constant ϵ(ω)=ϵ1(ω)+iϵ2(ω) along the c-axis in the antiferromagnetic insulating state of λ-(BEDT-TSF)2FeCl4 below TMI=8.3 K. The magnitude of ϵ1 is quite large in the order of 103 to 104 in contrast to 45 at microwave frequencies. Both ϵ1 and ϵ2 increase very drastically on approaching to TMI, suggesting some divergent behavior near TMI. [Copyright &y& Elsevier]