They grow outward, producing large, rounded masses which can cause what is known as a "mass effect". This growth can cause compression of local tissues or organs, leading to many effects, such as blockage of ducts, reduced blood flow (ischaemia), tissue death (necrosis) and nerve pain or damage. Some tumors also produce hormones that can lead to life-threatening situations. Insulinomas can produce large amounts of insulin, causing hypoglycemia. Pituitary adenomas can cause elevated levels of hormones such as growth hormone and insulin-like growth factor-1, which cause acromegaly; prolactin; ACTH and cortisol, which cause Cushings disease; TSH, which causes hyperthyroidism; and FSH and LH. Bowel intussusception can occur with various benign colonic tumors. Cosmetic effects can be caused by tumors, especially those of the skin, possibly causing psychological or social discomfort for the person with the tumor. Vascular tissue tumors can bleed, in some cases leading to anemia. Causes
PTEN hamartoma syndrome
PTEN hamartoma syndrome encompasses hamartomatous disorders characterized by genetic mutations in the PTEN tumor suppressor gene, including Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, Proteus syndrome and Proteus-like syndrome. Absent or dysfunctional PTEN protein allows cells to over-proliferate, causing hamartomas. Cowden syndrome is an autosomal dominant genetic disorder characterized by multiple benign hamartomas (trichilemmomas and mucocutaneous papillomatous papules) as well as a predisposition for cancers of multiple organs including the breast and thyroid. Bannayan–Riley–Ruvalcaba syndrome is a congenital disorder characterized by hamartomatous intestinal polyposis, macrocephaly, lipomatosis, hemangiomatosis and glans penis macules. Proteus syndrome is characterized by nevi, asymmetric overgrowth of various body parts, adipose tissue dysregulation, cystadenomas, adenomas, vascular malformation.
Hypertelorism is an abnormally increased distance between two organs or bodily parts, usually referring to an increased distance between the orbits (eyes), or orbital hypertelorism. In this condition the distance between the inner eye corners as well as the distance between the pupils is greater than normal. Hypertelorism should not be confused with telecanthus, in which the distance between the inner eye corners is increased but the distances between the outer eye corners and the pupils remain unchanged.Hypertelorism is a symptom in a variety of syndromes, including Edwards syndrome (trisomy 18), 1q21.1 duplication syndrome, basal cell nevus syndrome, DiGeorge syndrome and Loeys–Dietz syndrome. Hypertelorism can also be seen in Apert syndrome, Autism spectrum disorder, craniofrontonasal dysplasia, Noonan syndrome, neurofibromatosis, LEOPARD syndrome, Crouzon syndrome, Wolf–Hirschhorn syndrome, Andersen–Tawil syndrome, Waardenburg syndrome and cri du chat syndrome, along with piebaldism, prominent inner third of the eyebrows, irises of different color, spondyloepiphyseal dysplasia, mucopolysaccharide metabolism disorders (Morquio syndrome and Hurlers syndrome), deafness and also in hypothyroidism. Some links have been found between hypertelorism and attention deficit hyperactivity disorder. Embryology
Because hypertelorism is an anatomic condition associated with a heterogeneous group of congenital disorders, it is believed that the underlying mechanism of hypertelorism is also heterogeneous.