A persistent cloaca (from the term cloaca, an analogous orifice in birds, reptiles and amphibians), in which the rectum, vagina and urinary tract are joined into a single channel.Imperforate anus is usually present along with other birth defects—spinal problems, heart problems, tracheoesophageal fistula, esophageal atresia, renal anomalies and limb anomalies are among the possibilities, collectively being called the VACTERL association. Associated anomalies
Imperforate anus is associated with an increased incidence of some other specific anomalies as well, together being called the VACTERL association.Other entities associated with an imperforate anus are trisomies 18 and 21, the cat-eye syndrome (partial trisomy or tetrasomy of a maternally derived chromosome 22), Baller–Gerold syndrome, Currarino syndrome, caudal regression syndrome, FG syndrome, Johanson–Blizzard syndrome, McKusick–Kaufman syndrome, Pallister–Hall syndrome, short rib–polydactyly syndrome type 1, Townes–Brocks syndrome, 13q deletion syndrome, urorectal septum malformation sequence and the OEIS complex (omphalocele, exstrophy of the cloaca, imperforate anus, spinal defects). Diagnosis
When an infant is born with an anorectal malformation, it is usually detected quickly as it is a very obvious defect. Doctors will then determine the type of birth defect the child was born with and whether or not there are any associated malformations. It is important to determine the presence of any associated defects during the newborn period in order to treat them early and avoid further sequelae. There are two main categories of anorectal malformations: those that require a protective colostomy and those that do not.
But other studies had showed no association when corrected for age. Pathogenesis
At the cellular level, any abnormalities in the placental trophoblastic proliferation could potentially contribute to molar pregnancy and tumor development. There are three different types of trophoblasts: cytotrophoblasts, syncytiotrophoblasts, and intermediate trophoblasts. Each of them possesses distinct specialized functions to support a developing embryo. Cytotrophoblasts are the germinating cells that forms the chorion villi and can be differentiated into syncytiotrophoblasts which produce hCG and can intrude to the inner muscle layer of the uterus to help embed the developing embryo, and intermediate trophoblasts which spread throughout the chorion villi to support maternal-fetal circulation. Malignant cellular transformation of all of these three trophoblastic cells contribute to the development of gestational choriocarcinoma. Common pathological features of GC include abnormal trophoblastic enlargement, loss of trophoblastic specialized features and functions, absence of villi in the placenta, abnormal bleeding, and necrosis.Many efforts have been made to try to understand the mechanism of how non-malignant mole could become invasive. It is suspected that activation of certain oncogenes (such as up-regulations of MDM2, c-ERB2, and BLC2) and inactivation of tumor suppressor genes (such as up-regulations of p53, p21) were involved in the processes of genetic changes in this malignant transformation. But trophoblastic cells, by nature, are highly active in cell division, the increased activities of those genes are also necessary to maintain their normal cell function. Therefore, it is still unclear how significantly these genetic changes are in the pathogenesis of gestational choriocarcinoma.