Non-randomness of the anatomical distribution of tumors

Background: Why does a tumor start where it does within an organ? Location is traditionally viewed as a random event, yet the statistics of the location of tumors argues against this being a random occurrence. There are numerous examples including that of breast cancer. More than half of invasive breast cancer tumors start in the upper outer quadrant of the breast near the armpit, even though it is estimated that only 35 to 40% of breast tissue is in this quadrant. This suggests that there is an unknown microenvironmental factor that significantly increases the risk of cancer in a spatial manner and that is not solely due to genes or toxins. We hypothesize that tumors are more prone to form in healthy tissue at microvascular ‘hot spots’ where there is a high local concentration of microvessels providing an increased blood flow that ensures an ample supply of oxygen, nutrients, and receptors for growth factors that promote the generation of new blood vessels. Results: To show the plausibility of our hypothesis, we calculated the fractional probability that there is at least one microvascular hot spot in each region of the breast assuming a Poisson distribution of microvessels in two-dimensional cross sections of breast tissue. We modulated the microvessel density in various regions of the breast according to the total hemoglobin concentration measured by near infrared diffuse optical spectroscopy in different regions of the breast. Defining a hot spot to be a circle of radius 200 μm with at least 5 microvessels, and using a previously measured mean microvessel density of 1 microvessel/mm2, we find good agreement of the fractional probability of at least one hot spot in different regions of the breast with the observed invasive tumor occurrence. However, there is no reason to believe that the microvascular distribution obeys a Poisson distribution. Conclusions: The spatial location of a tumor in an organ is not entirely random, indicating an unknown risk factor. Much work needs to be done to understand why a tumor occurs where it does. Electronic supplementary material The online version of this article (10.1186/s41236-017-0006-7) contains supplementary material, which is available to authorized users

Gastric Outlet Obtruction by a Donor Aortic Tube After En Bloc Liver Pancreas Transplantation : A Case Report

We present the case of a 30-years-old female suffering from a type five maturity onset diabetes of the young deficiency, resulting in type 1 diabetes and terminal renal inssufficiency. She also had chronic and refractory pruritis due to primary sclerosing cholangitis _like fibrosis. She underwent combined en bloc liver and pancreas transplantation and kidney transplantation.The postoperative course was complicated by a gastric outlet obstruction due to compression of the native gastroduodenal junction by the donor aortic tube . This was treated by construction of a roux-en-y gastrojejunostomy at posttransplant day 24. To our knowledge, compression of the gastroduodenal junction by a donor aortic tube after combined liver and pancreas (or multivisceral) transplantation has not been reported previously

Gastric Bypass as a Revisional Procedure

The second edition of Minimally Invasive Bariatric Surgery provides a comprehensive, state-of-the art review of this field, and it serves as a valuable resource for clinicians, surgeons and researchers with an interest in minimally invasive bariatric surgery. Additionally, the second edition includes new features that will benefit the resident, fellow, or bariatric surgeon new to the field. Specifically, each evidence-based chapter (i.e. outcomes, complications, epidemiology, etc) concludes with three or four exam questions that emphasize the salient points of the chapter and provide fellowship programs a valuable training tool and resource for their academic curriculum. These questions are either single-answer multiple choice or true/false format and the correct response with a brief explanation follows. As more emphasis is placed on completing a comprehensive curriculum and obtaining certification for bariatric training, this aspect of the book is unique and provides added value to the text. The new edition also incorporates many new or updated medical illustrations to enhance the technique chapters and provide more uniformity for the artwork throughout the book. Each of the major procedures include surgical technique, outcomes, and management of complications in separate chapters to provide an easy reference for the busy clinician preparing for a case or presentation. Another unique feature of the text is a link to video files hosted online for the relevant chapters. This video library will be of great value to the user. As the number of fellowships in laparoscopic bariatric surgery continues to increase, this updated text will provide a valuable resource for general and bariatric surgeons, laparoscopic surgeons, fellows, residents, medical students, obesity researchers, and industry representatives involved in this fiel