The lesion may occur within the choroid, between Bruchs membrane and retinal pigment epithelium, or between the retinal pigment epithelium and photoreceptors. Despite the differences in location, the white dots all are of similar composition. The center of the lesion consists of macrophages and epithelioid cells. CD4+ T cells are on the periphery of the granuloma. Benezra has theorized that a large amount of CD8+ T suppressor cells are observed in the later stages of the disease in order to down regulate the inflammatory immune reaction.The formation of a granuloma occurs when activated antigen presenting cells, specifically dendritic cells, "bind to T cells and induce…the release of pro-inflammatory cytokines and chemokines." This response attracts additional antigen presenting cells and will eventually become a granuloma. Choroidal dendritic cells span several levels within the choroid and also associate with the retinal pigment epithelium. Usually, the dendritic cells disappear after removing the antigen. If removal did not occur, the formation of a granuloma would result. The white color of the dots when illuminated may be due to the granulomas composed only of "white cells". Each granuloma will disappear leaving no trace of its presence but in some cases it may leave a punched out scar. It is important to note that the formation of white dots may occur more frequently but is undetected. In normal cases, inflammation of the retina or choroid does not occur.
Pancreatic divisum is a congenital anomaly in the anatomy of the ducts of the pancreas in which a single pancreatic duct is not formed, but rather remains as two distinct dorsal and ventral ducts. Most individuals with pancreas divisum remain without symptoms or complications. A minority of people with pancreatic divisum may develop episodes of abdominal pain, nausea or vomiting due to acute or chronic pancreatitis. The presence of pancreas divisum is usually identified with cross sectional diagnostic imaging, such as MRI or computed tomography (CT) imaging. In some cases, endoscopic retrograde cholangiopancreatography (ERCP) is performed, revealing the diagnosis of pancreas divisum. If no symptoms or complications are present, then treatment is not necessary. However, if there is recurrent pancreatitis, then a sphincterotomy of the minor papilla may be indicated. Causes
The human embryo begins life with two ducts in the pancreas, the ventral duct and the dorsal duct. Normally, the two ducts will fuse together to form one main pancreatic duct; this occurs in more than 90% of embryos. In approximately 10% of embryos the ventral and dorsal ducts fail to fuse together, resulting in pancreas divisum. In utero, the majority of the pancreas is drained by the dorsal duct which opens up into the minor duodenal papilla. The ventral duct drains the minority of the pancreas and opens into the major duodenal papilla. In adults however, this situation is reversed whereby 70% of the pancreas is drained by the ventral duct.