Mycosis fungoides is a rare type of skin lymphoma, which is a cancer that originates in the lymphatic system. It primarily affects the skin, leading to patches, plaques, or tumors that can be itchy and may resemble eczema or psoriasis. The condition is a form of cutaneous T-cell lymphoma, where abnormal T-cells grow uncontrollably. The exact cause of mycosis fungoides is not well understood, but it is believed to involve genetic and environmental factors. Diagnosis typically involves a skin biopsy to examine the affected tissue. Treatment options may include topical therapies, phototherapy, and systemic medications, depending on the stage of the disease.