Mycosis Fungoides: Causes

Pathogenesis (disease development)

Mycosis fungoides is a disease that originates in the T cells of lymphoid tissue. It is thought to have a multicausal (caused by many factors) pathogenesis. In part, mycosis fungoides develops via prelymphomas such as large-bore or poikilodermatous (variegated) parapsoriasis (psoriasis; chronic skin disease resembling psoriasis) or lamphomatoid papulosis (chronic disease with recurrent/recurrent papules and nodules). There may also be antigen stimulation of T lymphocytes with stepwise malignancy (malignancy) via mutations to clonal neoplastic proliferation.In the premycotic stage, only a small number of skin-affinity tumor cells are initially found. It is predominantly inflammatory infiltrate.In the infiltrate stage, new skin foci develop due to the circulation of tumor cells with recirculation into the skin. Individual foci grow due to the increase in tumor cell number. The inflammatory reaction gradually subsides. New aggressive cell clones are formed. Eventually, extracutaneous (“outside the skin”) spread occurs due to tumor cell clones that no longer have an affinity for the skin.

Etiology (causes)

The etiology remains unclear to date. The following hypotheses exist:

  • Some affected individuals are found to have increased type IV allergic reactions, which may be due to increased activity of T cells.
  • Many patients have been exposed to chemicals. It is likely that individuals working in metal processing or agriculture are at increased risk for mycosis fungoides.
  • Chronic inflammation leads to persistent stimulation and proliferation (growth and multiplication of cells) of T cells.