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4 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Primary cutaneous follicle centre lymphoma is a slow-growing lymphoma of germinal-centre B cells that stays in the skin, usually as lumps on the head or trunk. Its outlook is excellent, with about 95 in 100 people alive at five years, and radiotherapy or excision is usually all that is needed; the important thing is not to mistake it for the aggressive leg-type large B-cell lymphoma.
WHO-HAEM5 lists primary cutaneous follicle centre lymphoma among the cutaneous B-cell lymphomas as a distinct entity from follicular lymphoma, defined by follicle centre cells in the skin with no extracutaneous disease at staging (Alaggio 2022). It has a five-year overall survival of about 95 percent against about 50 percent for primary cutaneous large B-cell lymphoma, leg type, and the two are separated in practice by IgM staining, present in all 40 leg-type cases and only 5 of 53 follicle centre cases in the defining study (Am J Surg Pathol 2010). Its molecular landscape differs from classic follicular lymphoma: 27 percent lack CD10 but all express MEF2B and HGAL, TNFRSF14 is the most commonly mutated gene (40 percent, with a further 10 percent carrying 1p36 deletions), followed by CREBBP, TNFAIP3, KMT2D, SOCS1, EP300, STAT6 and FOXO1, and BCL2 rearrangements are usually absent (Human Pathology 2020).
How it differs from its parent: it is skin-confined, rarely carries the t(14;18) that defines nodal follicular lymphoma, is not graded or staged as follicular lymphoma is, and is cured locally in most cases; the parent's chemoimmunotherapy is reserved for the rare disseminated case.
| Setting | Approach | Guideline |
|---|---|---|
| Solitary or localised | Local radiotherapy or excision. | not mapped |
| Multifocal or extracutaneous | Rituximab for multifocal skin disease; the parent's systemic pathways for the rare extracutaneous spread. | not mapped |