Mycosis fungoides

Mycosis fungoides is the most common form of cutaneous T-cell lymphoma – a chronic malignant disease of lymphocytes that primarily affects the skin. The disease progresses slowly, with gradual progression from spots to plaques and tumors. In the early stages, it often resembles eczema or psoriasis, which makes early diagnosis difficult.

Epidemiology and risk factors
- Occurs mainly in adults (50–70 years old)
- More common in men
- Causes are unknown; not considered an infectious disease
- No proven hereditary nature

Clinical stages
**1. Spotted stage:**
- Reddish, slightly scaly patches, often on the buttocks, thighs, and lower back
- Symmetrical arrangement
- Itching, but without severe inflammation

**2. Poster stage:**
- Thickened, reddish-violet plaques with scaling
- Lesion expansion and elevation

**3. Tumor stage:**
- Formation of tumors, sometimes ulcerating
- Possible spread beyond the skin – lymph nodes, internal organs

**Erythrodermic form (Sézary syndrome):**
- Diffuse redness and peeling of the entire skin
- Generalized lymphadenopathy and Sézary cells in peripheral blood

Diagnosis
It is based on a combination of:
- Clinical picture
- Multiple skin biopsies with histology and immunohistochemistry
- Immunophenotyping (CD3+, CD4+, CD7–)

- Staging tests – CT scan, blood count, lymph node biopsy

Treatment
Treatment depends on the stage of the disease:
**Early stages (spots and plaques):**
- Topical corticosteroids
- Calcineurin inhibitors
- Phototherapy (UVB, PUVA)
- Local chemotherapy (nimustine, mechlorethamine)
- Photodynamic therapy

**Advanced stages (tumors, erythroderma):**
- Systemic therapy (retinoids)
- Mono- or poly-chemotherapy in progressive form
- Immunotherapy

Forecast
The course of mycosis fungoides is chronic, often with years of stability in the early stages. The prognosis depends on the stage at diagnosis:
- Spotty/plaque stage – good prognosis
- Tumor/erythrodermic stage – worse prognosis
- Internal organ involvement – unfavorable outcome

Mycosis fungoides is a rare but treatable form of cutaneous lymphoma, especially when diagnosed early. An individualized approach and multidisciplinary follow-up play a crucial role in long-term disease control.