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Health condition · Clinically reviewed

Cutaneous B-cell lymphoma, from indolent skin plaques to leg-type DLBCL.

A rare skin lymphoma with very different subtypes. Most cases are indolent and highly treatable with local radiotherapy; a smaller group needs the same chemoimmunotherapy used for systemic large B-cell lymphoma.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against WHO-EORTC 2018, BAD, EORTC/ISCL consensus and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK skin lymphoma pathways including low-dose radiotherapy, rituximab and CAR-T for aggressive disease.

Key facts

CBCL at a glance.

The essentials, in plain English - what it is, how it is classified and what treatment looks like across UK skin lymphoma centres.

  • What it is

    A group of primary cutaneous lymphomas arising from B lymphocytes in the skin, accounting for around 20 to 25% of all cutaneous lymphomas.

  • WHO-EORTC 2018 types

    Marginal zone (PCMZL), follicle centre (PCFCL), diffuse large B-cell leg type (PCDLBCL-LT) and rarer entities.

  • Indolent subtypes

    PCMZL and PCFCL are slow-growing with an excellent prognosis and often need only local treatment.

  • Aggressive subtype

    PCDLBCL leg type presents as rapidly growing tumours on the lower limbs in older adults and needs systemic chemoimmunotherapy.

  • Peak age

    Most commonly diagnosed in the 50s to 70s, though it can occur at any adult age.

  • Diagnosis

    Deep skin biopsy with immunohistochemistry and molecular testing, followed by staging to rule out systemic lymphoma.

Why this guide matters

Subtype is everything in CBCL.

Because indolent and aggressive CBCL behave so differently, the three points below shape everything else on this page.

  • Indolent CBCL is highly treatable

    PCMZL and PCFCL are slow-growing and often controlled with low-dose local radiotherapy or intralesional therapy alone.

  • Leg-type DLBCL needs systemic care

    PCDLBCL leg type is aggressive and treated like systemic diffuse large B-cell lymphoma with R-CHOP and, sometimes, CAR-T for relapse.

  • Specialist MDT care changes outcomes

    CBCL is best managed through a supra-regional UK skin lymphoma centre with dermatology, haematology, oncology and radiotherapy at the same table.

How the diagnosis is made

From skin biopsy to a subtype and a stage.

The pathway a UK dermatology and haematology team will normally follow to reach a WHO-EORTC classification and TNM cutaneous lymphoma stage.

  1. 01

    Assessing

    Full skin and node examination

    Mapping every lesion by site, size and morphology and checking all lymph node groups, liver and spleen.

  2. 02

    Assessing

    Deep, adequate skin biopsy

    Essential first investigation - a punch or incisional biopsy that includes the subcutis so the pathologist can see architecture.

  3. 03

    Assessing

    Immunohistochemistry panel

    CD20, CD5, CD10, BCL-2, BCL-6, MUM1 and Ki-67 to classify the subtype and separate cutaneous from nodal disease.

  4. 04

    Confirming

    Molecular studies

    IGH clonality confirms a B-cell clone; MYD88 and CD79B mutations support leg-type DLBCL when present.

  5. 05

    Confirming

    Bloods and virology

    FBC, LDH, blood film, serum immunoglobulins, HIV, hepatitis B and C, and Borrelia serology where European exposure is possible.

  6. 06

    Confirming

    Cross-sectional imaging

    CT or PET-CT of neck, chest, abdomen and pelvis to exclude systemic disease and confirm the lymphoma is primarily cutaneous.

  7. 07

    Preparing

    Bone marrow and MDT staging

    Bone marrow biopsy for aggressive or equivocal cases, then TNM cutaneous lymphoma staging at a specialist skin lymphoma MDT.

Typical timeline: from first biopsy to full staging in a few weeks at a specialist centre.

Symptoms

What CBCL actually looks like.

Slowly growing red-purple papules and plaques in indolent disease; rapidly enlarging leg tumours in aggressive PCDLBCL leg type.

  • Solitary papule or nodule

    A single red or violaceous bump that has been slowly enlarging over months, often on the head, trunk or back.

  • Grouped plaques

    Clustered plum-coloured plaques on the scalp, forehead or upper back, classic for follicle centre lymphoma.

  • Multifocal lesions

    Several lesions in different body regions, most often seen in marginal zone lymphoma and sometimes linked to Borrelia in Europe.

  • Rapidly growing leg tumours

    Firm, red-blue tumours on one or both lower legs in older adults - the hallmark of leg-type diffuse large B-cell lymphoma.

  • Ulceration and bleeding

    Breakdown of the skin surface, weeping or bleeding tumours - more common in aggressive PCDLBCL leg type.

  • Slow, indolent behaviour

    Lesions may wax and wane for years - a pattern typical of indolent PCMZL and PCFCL.

  • Systemic B symptoms

    Fevers, drenching night sweats or unintended weight loss are unusual and should prompt urgent staging.

  • Red flag - fast growth or ulceration

    Any rapidly enlarging skin tumour, especially on the leg in an older adult, needs same-week dermatology and haematology review.

Treatment

How CBCL is treated in the UK.

Local radiotherapy or intralesional therapy for most indolent lesions, rituximab for multifocal indolent disease, and R-CHOP with novel agents or CAR-T for aggressive leg-type DLBCL.

  • Local radiotherapy

    Highly effective first-line for localised indolent CBCL. Low-dose regimens such as 4 Gy in 2 fractions can achieve complete response in most cases.

  • Surgical excision

    Selected solitary indolent lesions may be excised, particularly when radiotherapy is not preferred or accessible.

  • Intralesional therapy

    Intralesional steroid or rituximab for a small number of indolent lesions where systemic or radiation therapy is not required.

  • Topical treatments

    Potent topical steroids or topical tacrolimus can settle superficial indolent lesions and support other therapies.

  • Antibiotics for Borrelia

    Where Borrelia burgdorferi serology is positive, a course of doxycycline may be trialled before other treatment in European PCMZL.

  • Rituximab

    Intravenous anti-CD20 monoclonal antibody for multifocal indolent CBCL and part of chemoimmunotherapy for aggressive disease. See our rituximab infusion clinic guide.

  • R-CHOP chemoimmunotherapy

    Six cycles of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone for PCDLBCL leg type, mirroring systemic DLBCL protocols.

  • CAR-T and novel agents

    CAR-T cell therapy (axi-cel, tisa-cel, liso-cel), lenalidomide, ibrutinib and polatuzumab vedotin for relapsed or refractory aggressive CBCL.

What this guide is based on

The sources behind every claim on this page.

International classification and UK national guidance for cutaneous lymphomas, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your dermatology and haematology teams know your case and can tell you which parts apply to you. If in doubt, contact your specialist nurse.

  • WHO-EORTC classification of cutaneous lymphomas 2018 update.

  • British Association of Dermatologists (BAD). Guidelines for the management of primary cutaneous lymphomas.

  • EORTC and ISCL consensus recommendations on primary cutaneous B-cell lymphomas.

  • NICE guidance on non-Hodgkin lymphoma and specialist commissioning for skin lymphoma centres in England.

  • POLARIX trial and NHS England commissioning policy for CAR-T cell therapy in relapsed or refractory DLBCL.

Red flags

When CBCL needs urgent attention.

Signs that a lesion or treatment complication needs the specialist skin lymphoma team, urgent haematology or A&E.

  • Rapidly growing leg tumour

    A new, quickly enlarging red or blue nodule on the shin or calf in an older adult should be biopsied urgently to exclude PCDLBCL leg type.

  • Ulceration and bleeding

    Breakdown of a lymphoma lesion needs prompt wound care, culture and haematology review to guide systemic therapy.

  • B symptoms

    Persistent fevers, drenching night sweats or unintentional weight loss should trigger urgent staging with imaging and bone marrow assessment.

  • New lymphadenopathy or splenomegaly

    Any suggestion that disease has moved beyond the skin needs a full haematology work-up and MDT review.

  • Central nervous system symptoms

    Headache, neurological signs or cranial nerve issues in aggressive CBCL should prompt urgent imaging and consideration of CNS prophylaxis.

  • Neutropenic fever during chemo

    A temperature of 38 degrees or more during R-CHOP is a medical emergency - go to A&E with your alert card.

  • CAR-T cytokine release syndrome

    Fever, low blood pressure or breathlessness in the weeks after CAR-T infusion needs immediate specialist review.

  • Second malignancy or new skin lesion

    Any new suspicious skin lesion during follow-up should be examined and biopsied where indicated.

  • Severe infection risk

    Rituximab and chemoimmunotherapy suppress immunity - shingles, PJP and hepatitis B reactivation must be actively watched for.

Living with it

A rare cancer, with well-mapped pathways.

Four things that make the biggest difference day to day - looking after the skin, staying with a specialist centre, using the charities and committing to long-term follow-up.

A quiet reminder

Even after complete response, keep the follow-up.

Indolent CBCL can recur years later and there is a lifetime risk of second skin cancers, so annual dermatology review is worth keeping.

  1. 01 Care

    Look after the skin

    Regular emollients, gentle cleansing and sun protection help the skin cope with lesions and treatment side effects.

  2. 02 Team

    Stay with your specialist centre

    CBCL is treated at UK skin lymphoma centres including St John's, Guy's, the Christie, St James's, the Beatson and Aberdeen.

  3. 03 Support

    Use the charities

    Lymphoma Action and Blood Cancer UK offer helplines, printed guides and peer support tailored to skin lymphoma.

  4. 04 Follow-up

    Commit to long-term surveillance

    Even after complete response, indolent CBCL can recur, so annual dermatology follow-up and skin self-checks matter.

Frequently asked

Everything we get asked about cutaneous B-cell lymphoma.

Quick answers on subtypes, diagnosis, radiotherapy, rituximab, R-CHOP and CAR-T.

  • What is cutaneous B-cell lymphoma?

    Cutaneous B-cell lymphoma (CBCL) is a group of rare lymphomas that arise from B lymphocytes in the skin. It accounts for around 20 to 25% of all primary cutaneous lymphomas, with most cases being T-cell in origin. The WHO-EORTC 2018 classification recognises marginal zone lymphoma (PCMZL), follicle centre lymphoma (PCFCL), diffuse large B-cell lymphoma leg type (PCDLBCL-LT) and several rarer entities.

  • Is CBCL a cancer, and is it curable?

    Yes, CBCL is a form of blood cancer that presents primarily in the skin. Prognosis depends heavily on the subtype. The indolent forms (PCMZL and PCFCL) have five-year survival above 95% and are often controlled with local radiotherapy alone. PCDLBCL leg type is aggressive but can be curable with R-CHOP chemoimmunotherapy and, for relapsed cases, CAR-T cell therapy.

  • How is CBCL diagnosed?

    Diagnosis requires a deep skin biopsy that includes the subcutis, sent for detailed immunohistochemistry (CD20, CD5, CD10, BCL-2, BCL-6, MUM1, Ki-67) and molecular tests such as IGH clonality and, in aggressive cases, MYD88 and CD79B mutations. Staging then involves bloods, virology (HIV, hepatitis B and C), Borrelia serology in Europe, CT or PET-CT imaging and a bone marrow biopsy in aggressive or equivocal cases.

  • How is indolent CBCL treated?

    For a single lesion or a small area of disease, low-dose local radiotherapy (often 4 Gy in 2 fractions) is highly effective and cures most patients. Alternatives include surgical excision, intralesional rituximab or steroid, potent topical steroids or, when Borrelia is positive, a trial of doxycycline. For multifocal indolent disease, intravenous rituximab is the mainstay, sometimes with chlorambucil, interferon alfa or topical mechlorethamine.

  • How is aggressive PCDLBCL leg type treated?

    Leg-type disease is treated like systemic diffuse large B-cell lymphoma with six cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone), often with central nervous system prophylaxis. Newer options include the Pola-R-CHP regimen (polatuzumab vedotin) for high-risk DLBCL and CAR-T cell therapy (axi-cel, tisa-cel, liso-cel) for relapsed or refractory disease. Lenalidomide and ibrutinib may be used in the relapsed setting.

  • Where in the UK is CBCL treated?

    CBCL is managed through specialist supra-regional skin lymphoma centres including St John's Institute of Dermatology at Guy's and St Thomas', the Christie in Manchester, St James's in Leeds, the Beatson in Glasgow and centres in Aberdeen and other cities. Care is co-ordinated by a multidisciplinary team of dermatologists, haematologists, oncologists, radiotherapists and specialist skin lymphoma nurses.

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