153 research outputs found
Unusual appearance of a pendulated gastric tumor : always think of GIST
Objective. To investigate the clinicopathological characteristics of gastrointestinal stromal tumor (GIST) with significant cystic changes and to assess the molecular genetic characteristics. Methods. In a 68-year-old man, a large abdominal tumoral mass was discovered incidentally. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of a large cystic lesion with multiple contrast-enhancing septae and papillary projections. No clear connection with any of the surrounding organs was identified. Malignancy could not be excluded, and surgery was indicated. During surgery, the large mass was found to be attached by a narrow stalk to the large curvature of the stomach. Results. The histological features and immunohistiochemical profile of the tumor cells (positivity for CD117 and CD34) were consistent with a gastrointestinal stromal tumor with a high risk of progressive disease according to the Fletcher classification. Diagnosis was confirmed by mutational analysis; this demonstrated mutation in exon 14 of PDGFRA. During the followup of 97 months, the patient had a cancer-free survival. Conclusions. This case demonstrates that gastrointestinal stromal tumors (GISTs) with extensive cystic degeneration should be considered in the differential diagnosis of a cystic abdominal mass
Superior mesenteric arterial branch occlusion causing partial jejunal ischemia: a case report
<p>Abstract</p> <p>Introduction</p> <p>Ischemic bowel disease comprises both mesenteric ischemia and colonic ischemia. Mesenteric ischemia can be divided into acute and chronic ischemia. These are two separate entities, each with their specific clinical presentation and diagnostic and therapeutic modalities. However, diagnosis may be difficult due to the vague symptomatology and subtle signs.</p> <p>Case presentation</p> <p>We report the case of a 68-year-old Caucasian woman who presented with abdominal discomfort, anorexia, melena and fever. A physical examination revealed left lower quadrant tenderness and an irregular pulse. Computed tomography of her abdomen as well as computed tomography enterography, enteroscopy, angiography and small bowel enteroclysis demonstrated an ischemic jejunal segment caused by occlusion of a branch of the superior mesenteric artery. The ischemic segment was resected and an end-to-end anastomosis was performed. The diagnosis of segmental small bowel ischemia was confirmed by histopathological study.</p> <p>Conclusion</p> <p>Mesenteric ischemia is a pathology well-known by surgeons, gastroenterologists and radiologists. Acute and chronic mesenteric ischemia are two separate entities with their own specific clinical presentation, radiological signs and therapeutic modalities. We present the case of a patient with symptoms and signs of chronic mesenteric ischemia despite an acute etiology. To the best of our knowledge, this is the first report presenting a case of acute mesenteric ischemia with segmental superior mesenteric artery occlusion.</p
Intussusception of the Small Intestine Caused by a Primary Melanoma?
Although the gastrointestinal tract is a fairly frequent site of melanoma metastases, reports of small bowel intussusception caused by melanoma are very rare. We report the case of a 77-year-old man who was admitted to our hospital with epigastric pain, melena and anaemia. After clinical examination, laboratory evaluation and radiological work-up the diagnosis of a jejunal intussusception was made. Exploratory laparoscopy revealed a large tumour arising from the jejunum, approximately 20 cm distal to the angle of Treitz. Small bowel resection with an end-to-end anastomosis was performed. Histological examination showed an intestinal melanoma. There are different theories concerning the origin of malignant melanoma in the small bowel. Although the small and large intestines normally contain no melanocytes, these cells have occasionally been found in the alimentary and respiratory tracts and even in lymph nodes, which supports the theory of a primary origin of melanoma at these sites. Since this was a solitary intestinal lesion and there was no history of cutaneous melanoma, we conclude that this could be an example of a very rare primary melanoma of the small intestine
Study of the rocky intertidal communities of central and northern California: Years III and IV
The study objectives are to describe seasonal and successional variation in rocky intertidal community structure; determine the response of rocky intertidal communities to natural and human-induced disturbances and correlate these responses with successional, seasonal, and latitudinal variation; and correlate life history information and oil toxicity data with data from this and other relevant studies. The Year III and IV report is for the third (1987) and fourth (1988) years of a five-year field experimental study investigating two biological assemblages, the Mytilus assemblage and the Endocladia/Mastocarpus papillatus assemblage, that are being studied at six sites along the California coast.
Volume I includes the report, Appendix A, and Appendix B.
Volume II includes Appendix C.
Volume III includes Appendix D.
Volume IV includes Appendix E and Appendix F.
Volume V includes Appendix G, Appendix H, and Appendix I
Orbit structure and (reversing) symmetries of toral endomorphisms on rational lattices
We study various aspects of the dynamics induced by integer matrices on the
invariant rational lattices of the torus in dimension 2 and greater. Firstly,
we investigate the orbit structure when the toral endomorphism is not
invertible on the lattice, characterising the pretails of eventually periodic
orbits. Next we study the nature of the symmetries and reversing symmetries of
toral automorphisms on a given lattice, which has particular relevance to
(quantum) cat maps.Comment: 29 pages, 3 figure
A combinatorial model for reversible rational maps over finite fields
We study time-reversal symmetry in dynamical systems with finite phase space,
with applications to birational maps reduced over finite fields. For a
polynomial automorphism with a single family of reversing symmetries, a
universal (i.e., map-independent) distribution function R(x)=1-e^{-x}(1+x) has
been conjectured to exist, for the normalized cycle lengths of the reduced map
in the large field limit (J. A. G. Roberts and F. Vivaldi, Nonlinearity 18
(2005) 2171-2192). We show that these statistics correspond to those of a
composition of two random involutions, having an appropriate number of fixed
points. This model also explains the experimental observation that,
asymptotically, almost all cycles are symmetrical, and that the probability of
occurrence of repeated periods is governed by a Poisson law.Comment: LaTeX, 19 pages with 1 figure; to be published in Nonlinearit
The effect of a southward interplanetary magnetic field on St\"ormer's allowed regions
The motion of a charged particle in a magnetic dipole has first been studied
by Stormer. The different applications of Stormer's theory to aurorae, cosmic
rays and Van Allen radiation belt particles are recalled in an historical
perspective. In this paper, we expand the Stormer theory in order to take into
account the effects produced by an additional uniform and stationary
interplanetary magnetic field (IMF) whose orientation is parallel or
antiparallel to the magnetic moment of the dipole. A new expression is derived
for the Stormer potential taking into account the additional IMF component. It
is shown how Stormer's allowed and forbidden zones are influenced by the
implementation of a northward or a southward IMF, and how a southward turning
of the IMF orientation makes it easier for Solar Energetic Particle and
Galactic Cosmic Rays to enter into the inner part of the geomagnetic field
along interconnected magnetic field lines.Comment: 24 Pages; 15 Figures; Tutorial Lecture Presented At The Cospar
Colloquium "Plasma Processes In Th Near-Earth Space: Interball And Beyond,
Sofia, Bulgaria, 5-10 200
Robotic gastric resection of large gastrointestinal stromal tumors
Abstract Background The stomach is the most common site for gastrointestinal stromal tumors (GIST) development. Surgical treatment consists of excision of the entire neoplastic mass, with sufficient surgical margins within healthy tissue. This can be achieved with different techniques ranging from wedge resections, typical gastric resections, right up to total gastrectomy. There aren't clear guidelines for the use of minimally invasive approach. Materials and methods From January 2011 to April 2012, 5 patients with presumed preoperative diagnosis of GIST were treated by robotic surgery at the Unit of Surgery and Advanced Oncologic Therapies, Forli Hospital, Forli, Italy. We report operative techniques, perioperative outcomes and follow-up. Results Lesions were localized at anterior wall of gastric antrum ( N = 2) and near pyloric area ( N = 3). Mean tumor size was 5 cm (range 4–7 cm). Surgical procedures were 5 distal gastrectomy. None intervention was converted to open surgery and there weren't major intraoperative complications. Median operative time was 240 min (range 210–300 min) and mean intraoperative blood loss was 96 ml (80–120 ml). All lesions had microscopically negative resection margins. Median follow-up was 13.5 months (range 12–15 months) with a disease-free survival rate of 100%. Conclusions Surgical robotic approach for large GISTs is feasibility and new evidences are needed to clarify the effective role of different surgical strategies
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