- M/C cutaneous T-cell lymphoma (CTCL) (constitutes > 50% of all cutaneous lymphomas)
- Indolent primary cutaneous lymphoma (PCL) (type of extranodal NHL)
- MF constitutes < 1% of total NHL cases
The first clinical description of mycosis fungoides (MF) was made in 1806 by Baron Jean-Louis Alibert, a French physician, who identified a 56-year-old man with skin tumors resembling mushrooms after having a desquamating rash over several months.
In 1975, Lutzner, Edelson, and associates introduced the term cutaneous T-cell lymphoma (CTCL) to describe the spectrum of skin-based lymphomas of T-cell origin, including classic MF and Sézary syndrome (SS).
- Folliculotropic MF (follicular cell lymphoma)
- Granulomatous slack skin (rare)
- Pagetoid reticulosis
- Human T-cell lymphotropic virus type 1 & 2 (HTLV-1/2) (associated with Adult T cell leukaemia/lymphoma)
Tumour cells originate from memory T cells or skin-homing CD4+ T cells expressing cutaneous lymphocyte antigen (CLA) and chemokine receptors CCR4 and CCR7.
Patch → Plaque → Tumour → Erythroderma: Sézary syndrome (SS)
Truncal scaling, red-brown patches, plaques and fungating nodules seen
- Earliest lesion: Erythematous/brownish scaly patch (may show slight atrophy)
- Plaque parapsoriasis: Single/multiple lesions of variable diameters and locations develop, often in covered areas and particularly in the gluteal region and on the proximal thighs.
- Multiple larger lesions with evident infiltration
- Annular/horseshoe-shaped lesions with an infiltrated base, raised, well-defined edges and asymmetrical distribution.
- May also affect the face and the scalp
- Erythematous-purplish papules or nodules of larger diameter seen
Sézary syndrome (SS):
- MF evolves into a systemic lymphoma with visceral and nodal spread.
Excisional skin biopsy:
- Pautrier microabscesses: tumour cells invade epidermis as single cells and small clusters
- Chronic eczema
- Atopic dermatitis
- Leprosy/lichenoid pityriasis
Tumor-node-metastasis-blood (TNMB) staging:
- Topical/systemic steroids
- Topical nitrogen mustard
- Phototherapy (UVB and PUVA)
- Total skin electron beam therapy (TSEBT)
- For local control of skin and nodal disease.