It is estimated that one case of urachal carcinoma for every 600 patients treated for bladder cancer. The urachus is a vestigial structure, which while important in some species, has no role in the development of human beings. The precursor initially urachal ligament arises from the cloaca at the end of the large intestine. During embryogenesis, the cloaca is divided to form the urogenital sinus, which develops in the bladder and sexual organs, and the anorectal canal, which becomes the rectum. The bladder is formed from the medial part of the urogenital sinus. Superior to this, in light of the allantois is obliterated to form the urachus. In adulthood, the urachus is attached to the obliterated umbilical arteries to form the commune of ligament. Although urachal ligament is most often connected with the dome of the bladder, can also attach to the back wall of the bladder or earlier, usually in the midline. A light remnant may persist in the bladder wall in the form of small tubular or cystic structures, and can communicate with the light of the bladder in up to one third of adults. Columnar cells, glandular islands, and the transitional cell epithelium may be present in a urachal remnant. When the malignancy is found to arise from this remnant, histology is the overwhelming intestinal adenocarcinoma.
Two theories have been proposed for the development of tumors of the urachus. One of them is that they come from intestinal adenocarcinomas is based on the left behind the cloaca during embryological development. This explains the histological similarity to adenocarcinomas of the rectum. An alternative hypothesis is that these tumors arise from metaplasia. Supportive evidence includes the occurrence of adenocarcinomas of the bladder epithelium despite exstrophic transition at birth, the occasional development of other tumors of intestinal type in the ureter and renal pelvis, which are not of sewage, and observation of adenocarcinoma arising from glandular cystitis.
What the details of its origin, it is clear that these types of cancer have a clinical manifestation that is very different from typical urothelial cancer. No risk factors have been identified, and in particular, smoking and other environmental factors figure prominently in the typical CTP do not seem relevant. Patients with cancer of the urachus are usually much younger, with a mean age of 47 to 57 years reported at diagnosis, with many cases reported in the third and fourth decades. In addition, these cancers occur equally in men and women (male / female ratio of TCC is approximately 3: 1), and show less susceptibility to cisplatin-based chemotherapy.
Most urachal tumors intestinal histology type display, similar to adenocarcinomas of the colon and rectum. These tumors are usually glandular structures with mucin production, colloid and / or histology of signet ring cells can be present.More rarely sarcomatoid carcinoma, and transitional cell histology have been reported. The epithelium remains normal to the surface or focally ulcerative tumor may overlap. Normal epithelium overlying the tumor strongly supports the diagnosis of urachal carcinoma. However, the destruction of this layer by the tumor can make the distinction between adenocarcinoma of the urachus and urachal bladder difficult. The presence of cystic glandular cystitis or cystitis transition to malignancy favors the diagnosis of adenocarcinoma of the bladder proper, as opposed to that of urachal origin.
Two theories have been proposed for the development of tumors of the urachus. One of them is that they come from intestinal adenocarcinomas is based on the left behind the cloaca during embryological development. This explains the histological similarity to adenocarcinomas of the rectum. An alternative hypothesis is that these tumors arise from metaplasia. Supportive evidence includes the occurrence of adenocarcinomas of the bladder epithelium despite exstrophic transition at birth, the occasional development of other tumors of intestinal type in the ureter and renal pelvis, which are not of sewage, and observation of adenocarcinoma arising from glandular cystitis.
What the details of its origin, it is clear that these types of cancer have a clinical manifestation that is very different from typical urothelial cancer. No risk factors have been identified, and in particular, smoking and other environmental factors figure prominently in the typical CTP do not seem relevant. Patients with cancer of the urachus are usually much younger, with a mean age of 47 to 57 years reported at diagnosis, with many cases reported in the third and fourth decades. In addition, these cancers occur equally in men and women (male / female ratio of TCC is approximately 3: 1), and show less susceptibility to cisplatin-based chemotherapy.
Most urachal tumors intestinal histology type display, similar to adenocarcinomas of the colon and rectum. These tumors are usually glandular structures with mucin production, colloid and / or histology of signet ring cells can be present.More rarely sarcomatoid carcinoma, and transitional cell histology have been reported. The epithelium remains normal to the surface or focally ulcerative tumor may overlap. Normal epithelium overlying the tumor strongly supports the diagnosis of urachal carcinoma. However, the destruction of this layer by the tumor can make the distinction between adenocarcinoma of the urachus and urachal bladder difficult. The presence of cystic glandular cystitis or cystitis transition to malignancy favors the diagnosis of adenocarcinoma of the bladder proper, as opposed to that of urachal origin.