• Skin-directed therapy in mycosis fungoides: creams, light and small radiotherapy fields: Early mycosis fungoides is treated on the skin, not through the bloodstream.
• Indolent and aggressive lymphoma: Lymphomas are split by how fast they grow, and the split decides what happens next.
• Lugano classification / Ann Arbor staging: The Lugano classification is the lymphoma staging system: stage I to IV by how many lymph node regions and organs are involved, with PET-based response criteria.
• Nodal and extranodal lymphoma: A lymphoma that starts in a lymph node is called nodal; one that starts in an organ is called extranodal.
• Radiotherapy in lymphoma: involved-site fields, 24 Gy, 4 Gy and total skin electron therapy: Lymphoma is one of the most radiation-sensitive cancers there is, so the doses are low and the fields are small.
• The two lymphoma classifications of 2022 (WHO-HAEM5 and ICC): Since 2022 there have been two reference classifications of lymphoma rather than one, published within months of each other by overlapping groups of experts.

Biomarker results to ask for: CD30 on more than three-quarters of the large cells, which defines the group, Absence of ALK; an ALK-positive skin tumour is usually systemic disease that has reached the skin, Staging to confirm there is no disease outside the skin, which changes both the diagnosis and the treatment, A clonal T-cell receptor rearrangement, which may be shared with coexisting lymphomatoid papulosis, Whether the skin disease is localised or widespread, which the consensus recommendations use to choose treatment.

Scans and tests linked to this cancer: FDG PET, Histopathology & immunohistochemistry.

Bring copies of scan reports, pathology and blood results, and a list of every medicine and supplement.

• Confirming it is confined to the skin: The diagnosis cannot be made on the biopsy alone, because the cells look identical to those of systemic anaplastic large cell lymphoma. It requires staging that shows no disease outside the skin, and a clinical history: how long the lesion has been there, whether others have come and gone, and whether the person has lymphomatoid papulosis or mycosis fungoides, which coexist with it. An ALK-positive skin tumour is usually systemic disease that has reached the skin, and is staged and treated as such. (Histopathology & immunohistochemistry, CD30, FDG PET, Lymphomatoid papulosis, Lugano classification / Ann Arbor staging)
• A single lesion or a few in one area, which is most patients: Surgical excision or local radiotherapy. Both work; the choice is made on the site, the size and what will heal well. Lesions recur in a substantial proportion of patients, 42 per cent in the Stanford series, and recurrence in the skin is expected rather than a treatment failure: it is treated the same way again. Up to a quarter of lesions regress partly or completely without any treatment, so observing a lesion that is already shrinking is reasonable. (Palliative radiotherapy, Skin-directed therapy in mycosis fungoides: creams, light and small radiotherapy fields, Radiotherapy in lymphoma: involved-site fields, 24 Gy, 4 Gy and total skin electron therapy)
• Widespread skin disease, or disease beyond the skin: Low-dose weekly methotrexate for disease that keeps recurring in many places. Brentuximab vedotin for widespread or extracutaneous disease: ALCANZA randomised patients with CD30-positive mycosis fungoides or primary cutaneous anaplastic large cell lymphoma to brentuximab vedotin against the physician's choice of methotrexate or bexarotene, and the figures are on the cutaneous T-cell lymphoma page. Combination chemotherapy is reserved for disease outside the skin: it produces short remissions and real harm in a disease otherwise controlled for decades, and over-treatment is the commonest avoidable harm here. (Methotrexate, Brentuximab vedotin, ALCANZA, Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome), Skin-directed therapy in mycosis fungoides: creams, light and small radiotherapy fields)

From the standard of care recorded for this cancer; which apply depends on your stage and biomarkers. Ask which the team recommends and why.