It is an extremely rare medical condition characterized by hands and feet hyperkeratosis and the association with an esophageal cancer. For this reason, it is sometimes known as tylosis with esophageal cancer (TOC). It is an autosomal dominant inherited disorder.
Tylosis with Esophageal Cancer (TOC); Howel-Evans Syndrome; Keratosis Palmoplantaris with Adenocarcinoma of the Colon/Esophagus; Clarke Howel-Evans Syndrome; Clarke Howel-Evans-McConnell Syndrome; Bennion-Patterson Syndrome.
First reported by Clarke and McConnell in 1954 and further studied by William Howel-Evans et al in 1958.
Unknown. Originally described in two families from Liverpool, UK. The syndrome has now also been described in many other countries and ethnicities. The most clear defined hereditary predisposition associated with palmoplantar keratoderma (PPK) is the presence of an esophagus squamous cell cancer (ESCC). It is the most common form of cancer in women (20.2%) and second in men (10.7%) when combined to all cancer cases diagnosed in Van Region in the east of Turkey. Ninety percent of all esophageal cancer cases are ESCC and 20 to 30% of them have family history of esophageal cancer and PPK.
A wide heterogeneity and variety of genes have been implicated. It is most often inherited as an autosomal dominant trait with full penetrance. The TOC gene is located in the 17q23-qter region, telomeric to the type I keratin gene cluster. Regions 17q24 and 17q25 may also be involved.
The cause of tylosis and esophageal carcinoma is unknown, but the association with cancer may represent a contiguous gene syndrome.
Based on the findings of palmoplantar keratosis, oral leukoplakia, and squamous cell carcinoma of the esophagus. Hyperkeratosis limited to palms and soles, with the keratoderma stopping abruptly at the lateral margins and not extending onto the dorsum. The epidermis from biopsies of affected skin sites shows gross acanthosis, hyperkeratosis, and hypergranulosis.
The association of hyperkeratosis of soles and palms with various malignancies in several members of a family is characteristic for this syndrome. Tylosis usually appears between 5 and 15 years of age. The typical neoplastic manifestation is carcinoma of the esophagus and colon, but there is also an increased risk for other malignancies such as endometrial carcinoma or melanoma. Hyperkeratosis can also be found in other areas that are repeatedly exposed to mechanical trauma, and oral leukoplakia is common. Typically, hyperkeratosis appears in adolescence, and malignancies occur after the third decade of life. Development of esophageal carcinoma after the third decade is almost certain, estimated to be 95% by age 65 years. Recognition of tylosis allows better surveillance for the development of esophageal cancers.