Although some cases have been reported, there is not enough evidence to indicate an association between Cowden syndrome and the development of male breast cancer. Up to 75% demonstrate benign breast conditions such as intraductal papillomatosis, fibroadenomas, and fibrocystic changes. However, there is currently not enough evidence to determine if benign breast disease occurs more frequently in Cowdens patients as compared to individuals without a hereditary cancer syndrome.Central Nervous System
Macrocephaly is observed in 84% of patients with Cowden syndrome. It typically occurs due to an abnormally enlarged brain, or megalencephaly. Patients may also exhibit dolichocephaly. Varying degrees of autism spectrum disorder and intellectual disability have been reported as well. Lhermitte-Duclos disease is a benign cerebellar tumor that typically does not manifest until adulthood in patients with Cowden syndrome. Genetics
Cowden syndrome is inherited in an autosomal dominant fashion. Germline mutations in PTEN (phosphatase and tensin homolog), a tumor suppressor gene, are found in up to 80% of Cowdens patients. Several other hereditary cancer syndromes, such as Bannayan-Riley-Ruvalcaba syndrome, have been associated with mutations in the PTEN gene as well. PTEN negatively regulates the cytoplasmic receptor tyrosine kinase pathway, which is responsible for cell growth and survival, and also functions to repair errors in DNA. Thus, in the absence of this protein, cancerous cells are more likely to develop, survive, and proliferate.Recently, it was discovered that germline heterozygous mutations in SEC23B, a component of coat protein complex II vesicles secreted from the endoplasmic reticulum, are associated with Cowden syndrome.
Chiari 1.5 is a term used when both brainstem and tonsillar herniation through the foramen magnum are present.The diagnosis of a Chiari II malformation can be made prenatally, through ultrasound. Classification
In the late 19th century, Austrian pathologist Hans Chiari described seemingly related anomalies of the hindbrain, the so-called Chiari malformations I, II and III. Later, other investigators added a fourth (Chiari IV) malformation. The scale of severity is rated I – IV, with IV being the most severe. Types III and IV are very rare. Since Dr. Chiaris original descriptions Chiari 0, 1.5, 3.5, and 5 have been described in the medical literature. Types of Chiari malformation
Other conditions sometimes causally associated with Chiari malformation include hydrocephalus, syringomyelia, spinal curvature, tethered spinal cord syndrome, and connective tissue disorders such as Ehlers-Danlos syndrome and Marfan syndrome. Chiari malformation is the most frequently used term for this set of conditions. The use of the term "Arnold–Chiari malformation" has fallen somewhat out of favor over time, although it is used to refer to the type II malformation. Current sources use "Chiari malformation" to describe its four specific types, reserving the term "Arnold-Chiari" for type II only. Some sources still use "Arnold-Chiari" for all four types.Chiari malformation or Arnold–Chiari malformation should not be confused with Budd-Chiari syndrome, a hepatic condition also named for Hans Chiari. In Pseudo-Chiari Malformation, leaking of CSF may cause displacement of the cerebellar tonsils and similar symptoms sufficient to be mistaken for a Chiari I malformation.