Primary Cutaneous Large B-Cell Lymphoma, Leg Type, Localized on the Dorsum

Primary cutaneous large B-cell lymphoma, leg-type (PCLBCL-LT), is a large B-cell lymphoma primarily involving the skin. It is distinguished from the other 3 subsets of this lymphoproliferative disorder by its immunohistopathological features, configuring confluent sheets of medium-sized to large B lymphocytes with round nuclei provided with evident nucleoli, resembling centroblasts or immunoblasts, which express Bcl-6, Bcl-2. Prevalently appearing on the lower limbs, as a single or multicentric and frequently ulcerated skin nodule or plaque, PCLBCL-LT has a worse prognosis than the other large B-cell lymphomas. Moreover, the age of onset is delayed (7th decade) compared to those of the other 3 subtypes (6th decade); it presents a slight female predominance (2:1), and a higher percentage of positivity to Bcl-2. We present a 52-year-old man who showed a 2-year standing, non-ulcerated, round, 4 cm in diameter, red plaque, medially located on the dorsum. After biopsy the diagnosis of PCLBCL-LT was made on histopathological and immunohistochemical studies, the latter showing positivity to CD20, Bcl-2, and Bcl-6. After treatment with radiotherapy the patient has shown a 4.4-year follow-up free of disease

Endobronchial ultrasound in Dieulafoy’s disease of the bronchus: an additional application of EBUS

Dieulafoy’s disease is a rare vascular malformation represented by an abnormally enlarged submucosal arterial vessel. This malformation is mostly found in gastrointestinal tract causing spontaneous bleeding although a few cases have been described in the bronchial tree. Recognizing Dieulafoy’s malformation is crucial for the bronchoscopist in order to avoid biopsy that can lead to a massive hemoptysis, sometimes fatal. In this case report we show the clinical utility of endobronchial ultrasound (EBUS) in the evaluation of bronchial alteration suspicious for Dieulafoy’s malformation

The transbonchial lung biopsy for diagnosis of diffuse parenchymal lung disease; Pro

The diagnosis of diffuse parenchymal lung disease (DPLD) may require invasive procedures after all noninvasive tools have failed. The clinical context in which these diseases develop and the radiological patterns are crucial for defining the timing and the methods to be used. After the introduction in clinical practice of HRCT scan, the evaluation of imaging patterns, along with the immunological status of the patient and the clinical course of the disease (acute vs. chronic) seem to be crucial to choose the best diagnostic procedure

Bunching visibility for correlated photons from single GaAs quantum dots

We study photon bunching phenomena associated with biexciton-exciton cascade in single GaAs self-assembled quantum dots. Experiments carried out with a pulsed excitation source show that significant bunching is only detectable at very low excitation, where the typical intensity of photon streams is less than the half of their saturation value. Our findings are qualitatively understood with a model which accounts for Poissonian statistics in the number of excitons, predicting the height of a bunching peak being determined by the inverse of probability of finding more than one exciton.Comment: 6 pages, 6 figs to appear in Phys. Rev.

Conduit Dynamics in Transitional Rhyolitic Activity Recorded by Tuffisite Vein Textures from the 2008–2009 Chaitén Eruption

The mechanisms of hazardous silicic eruptions are controlled by complex, poorly-understood conduit processes. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent. Such behavior hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. Intersection of foam domains by tuffisite veins appears critical to efficient outgassing. However, knowledge is currently lacking into textural heterogeneities within shallow conduits, their relationship with tuffisite vein propagation, and the implications for fragmentation and degassing processes. Similarly, the magmatic vesiculation response to upper conduit pressure perturbations, such as those related to the slip of dense magma plugs, remains largely undefined. Here we provide a detailed characterization of an exceptionally large tuffisite vein within a rhyolitic obsidian bomb ejected during transitional explosive-effusive activity at Chaitén, Chile in May 2008. Vein textures and chemistry provide a time-integrated record of the invasion of a dense upper conduit plug by deeper fragmented magma. Quantitative textural analysis reveals diverse vesiculation histories of various juvenile clast types. Using vesicle size distributions, bubble number densities, zones of diffusive water depletion, and glass H2O concentrations, we propose a multi-step degassing/fragmentation history, spanning deep degassing to explosive bomb ejection. Rapid decompression events of ~3–4 MPa are associated with fragmentation of foam and dense magma at ~200–360 m depth in the conduit, permitting vertical gas and pyroclast mobility over hundreds of meters. Permeable pathway occlusion in the dense conduit plug by pyroclast accumulation and sintering preceded ultimate bomb ejection, which then triggered a final bubble nucleation event. Our results highlight how the vesiculation response of magma to decompression events is highly sensitive to the local melt volatile concentration, which is strongly spatially heterogeneous. Repeated opening of pervasive tuffisite vein networks promotes this heterogeneity, allowing juxtaposition of variably volatile-rich magma fragments that are derived from a wide range of depths in the conduit. This process enables efficient but explosive removal of gas from rhyolitic magma and creates a complex textural collage within dense rhyolitic lava, in which neighboring fused clasts may have experienced vastly different degassing histories