Cutaneous T-cell lymphoma (CTCL) is a type of cancer that primarily affects the skin. It arises from a group of white blood cells called T-cells, which are part of the immune system. In CTCL, these T-cells become malignant and can lead to various skin symptoms, including rashes, lesions, and patches that may be itchy or painful. CTCL is considered a rare form of lymphoma and can progress slowly over time. Diagnosis typically involves a skin biopsy to examine the affected tissue. Treatment options may include topical therapies, phototherapy, and systemic medications, depending on the severity and stage of the disease.