Sézary syndrome is an aggressive form of a type of blood cancer called cutaneous T-cell lymphoma. Cutaneous T-cell lymphomas occur when certain white blood cells, called T cells, become cancerous; these cancers characteristically affect the skin, causing different types of skin lesions. In Sézary syndrome, the cancerous T cells, called Sézary cells, are present in the blood, skin, and lymph nodes. A characteristic of Sézary cells is an abnormally shaped nucleus, described as cerebriform.

The cause of Sézary syndrome is unknown. Most affected individuals have one or more chromosomal abnormalities, such as the loss or gain of genetic material. These abnormalities occur during a person's lifetime and are found only in the DNA of cancerous cells. Abnormalities have been found on most chromosomes, but some regions are more commonly affected than others. People with this condition tend to have losses of DNA from regions of chromosomes 10 and 17 or additions of DNA to regions of chromosomes 8 and 17. It is unclear whether these alterations play a role in Sézary syndrome, although the tendency to acquire chromosomal abnormalities (chromosomal instability) is a feature of many cancers. It can lead to genetic changes that allow cells to grow and divide uncontrollably.

Sézary syndrome is a rare condition, although its prevalence is unknown. It is the second most common form of cutaneous T-cell lymphoma after mycosis fungoides, accounting for approximately 3 to 5 percent of cases of cutaneous T-cell lymphoma.

The inheritance pattern of Sézary syndrome has not been determined. This condition occurs in people with no history of the disorder in their family and is not thought to be inherited in most cases.

Published Date: May 17, 2021
Published By: National Institutes of Health