Cutaneous B-cell lymphoma

Author: Vanessa Ngan, Staff Writer, 2005. Updated by Dr Sara de Menezes, Basic Physician Trainee, Alfred Health, Melbourne, Australia; Chief Editor: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, November 2016.

Cutaneous B-cell lymphoma — codes and concepts

What is cutaneous B-cell lymphoma?

Lymphomas are tumours of the lymph nodes and lymphatic system.

  • Extranodal lymphomas are tumours that occur in organs or tissues outside of the lymphatic system.  
  • Primary cutaneous lymphomas occur in the skin with no evidence of extracutaneous disease at the time of diagnosis 

Primary cutaneous lymphoma can be broadly divided into two categories:

Primary cutaneous B-cell lymphomas (PCBL) comprise approximately 20% of cutaneous lymphomas.

What are cutaneous B-cell lymphomas?

Cutaneous B-cell lymphomas are a malignant proliferation of lymphocytes of the B-cell type. Mutation occurring at different points in B cell development leads to differing forms of lymphoma.

In 2005, the World Health Organization (WHO) and European Organization for Research and Treatment of Cancer Classification (EORTC) reached a consensus classification for cutaneous lymphomas. It was revised by the WHO in 2008. The three main types of PCBCL are:

Rare cases of PCDLBCL that do not belong to the PCDLBCL-LT or PCFCL groups are categorised as PCDLBCL-other. Other entities such as anaplastic or plasmablastic lymphoma, primary cutaneous T-cell/histiocyte-rich B-cell lymphomas and primary cutaneous intravascular large B-cell lymphomas are very rare.

Due to differences in treatment and prognosis, it is important to discern between PCBCL and systemic forms of B-cell lymphomas that manifest with secondary skin involvement.  

Cutaneous B-cell lymphoma

Who gets cutaneous B-cell lymphoma?

Primary cutaneous follicle centre lymphoma (PCFCL)

  • Second most common lymphoma in the Western world
  • Most common type of PCBCL
  • 5-year survival about 95%
  • Affects older patients, median age 60 years

Primary cutaneous marginal zone B-cell lymphoma (PCMZL)

  • Men are affected twice as often as women
  • Some associated with Borrelia burgdorferi infection (the cause of Lyme disease) in endemic areas of Europe and the USA
  • Best 5-year survival of 99%
  • Younger patients affected, median age 55, but can also be found in children

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT)

  • Twice as common in women than it is in men
  • Worst prognosis, 5-year survival 50%
  • The elderly are affected, median age 76 years

Primary cutaneous diffuse large B-cell lymphoma, other (PCDLBCL-other)

  • Very rare
  • Variable prognosis

What are skin signs of cutaneous B-cell lymphoma?

Primary cutaneous follicle centre lymphoma

  • Solitary or grouped papules, plaques or nodules
  • Pink to violaceous
  • Found on scalp, forehead or trunk
  • Very rarely found on leg

Especially when involving the head or face, PCFCL can mimic rosaceafolliculitisacne, lupus miliaris (TB) and insect bites. The list of differential diagnoses should also include basal cell carcinomaMerkel cell carcinoma, cutaneous lymphoid hyperplasia and other non-B-cell cutaneous tumours (eg, cutaneous T-cell lymphomas).

Primary cutaneous marginal zone B-cell lymphoma

PCMZL is a low-grade malignant B-cell lymphoma of the MALT (mucosa-associated lymphoid tissue) type.  

  • Solitary or multiple papules, plaques or nodules
  • Red to violaceous
  • Most often found on trunk and upper extremities

Often the lesions appear minor clinically, and in some case reports, can mimic the appearance of basal cell carcinoma. Other differential diagnoses include arthropod bitesurticarialeukaemia cutis and medication-induced pseudolymphoma.

Primary cutaneous diffuse large B-cell lymphoma, leg type

  • Solitary or multiple nodules, infiltrated plaques and tumours
  • Rarely, presents as verrucous plaques or widespread garland-like lesions
  • Typically red to bluish
  • Mainly found on one or both legs, affects other sites in 10–15%
  • Represents an aggressive subtype of PCBCL
  • Multiple skin lesions on the leg have poor prognosis

Primary cutaneous diffuse large B-cell lymphoma, other

  • Large B-cell lymphoma presents with skin lesions on the head, the trunk or the extremities.
  • Blastic plasmacytoid dendritic cell neoplasm presents with bruise-like plaques, nodules and tumours. It later progresses to involve the central nervous system. It represents a type of leukaemia cutis.
  • Intravascular large B-cell lymphoma proliferates within the lumen of small blood vessels, primarily in the skin and central nervous system and later other organs. Lesions appear as erythematous, tender nodules, tumours, and telangiectases mainly on the trunk and lower legs. Cutaneous lesions may be confused with mycosis fungoidessarcoidosisblood vessel tumours, or leukaemia cutis.  
Intravascular large B-cell lymphoma

How is cutaneous B-cell lymphoma diagnosed? 

The work-up of PCBCLs should include a complete history, physical and skin examination. Initial blood tests should include:

  • Full blood count and differential
  • Metabolic profile and lactate dehydrogenase.

If the full blood count shows lymphocytosis, peripheral blood flow cytometry may be needed.

An adequate skin biopsy is also important for evaluation and staging. Either 4–6 mm punch, incisional or excisional biopsies should be obtained and should include the reticular dermis and subcutaneous fat. Superficial biopsy specimens may not differentiate PCBCLs from reactive or inflammatory processes.

Assessment for extra-cutaneous involvement should be done, particularly in patients with palpable lymphadenopathy.

  • Contrast CT scan
  • PET scan

Any lymph node identified on imaging  > 1.5 cm in length or showing high PET activity should undergo biopsy, excisional biopsy being preferred where possible.

Histologically, PCBCL show a diffuse monotonous population of centroblasts and immunoblasts.   Histochemistry tests are essential to classify the exact type of lymphoma.

Primary cutaneous follicle centre lymphoma 

PCFCL needs to be differentiated from a secondary cutaneous lymphoma, which is where a nodal follicular lymphoma has spread to involve the skin. Cellular morphology may vary with the age and size of the lesion.

Histologically, PCFCL shows:

  • Dermal and subcutaneous proliferation of centrocytes (cleaved follicle centre cells) and centroblasts (large transformed cells) in a follicular and/or diffuse growth pattern.

Immunostaining shows:

  • Positive B-cell antigens, ie CD20 and CD79a
  • Negative bcl-2 protein, and, the t(14;18) translocation (which if present may suggest systemic follicular lymphoma)
  • Negative immunoglobulin M expression

FISH analysis is unhelpful.

Primary cutaneous marginal zone B-cell lymphoma

 The histology of PCMZL consists of:

  • Nodular to diffuse dermal infiltrates of marginal zone B-cells, lymphocytes, lymphoplasmacytoid cells, plasma cells admixed with reactive T cells and centroblast or immuneblast-like cells.
  • The marginal zone B-cells tend to be small to medium in size with irregular nuclei, inconspicuous nucleoli and abundant pale cytoplasm. They proliferate in the dermal and subcutaneous regions of skin.

Immunostaining shows

  • Positive CD20, CD79a and Bcl-2
  • Negative CD10 and Bcl-6.
  • Less than 25% of PCMZL harbor the t(14;18) translocation.
  • Expresses microRNAs 150 and 155 which, if present, may be predictive of longer progression-free survival.

Primary cutaneous large B-cell lymphoma, leg type

PCFCL and PCDLBCL-LT have diffuse large B-cell infiltrates. PCDLBCL-LT shows:

  • Diffuse dermal proliferation of centroblasts and immunoblasts in monotonous or confluent sheets
  • Larrge round nuclei with open chromatin, prominent nucleoli and identifiable mitotic figures.
  • Sparse T cells confined to perivascular areas.

Histopathological differential diagnoses should include:

  • Diffuse large B-cell lymphoma not otherwise specified (DLBCL NOS)
  • Epstein–Barr virus-positive DLBCL of the elderly
  • Lmphomatoid granulosis.

Immunostaining shows:

  • Positive CD20 and CD79a with strong expression of surface and cytoplasmic immunoglobulin M.
  • Strong expression of Bcl-2, MUM1/IRF4 and FOX-P1.
  • Any PCBCL showing both Bcl-2 and MUM1 expression should be classified as leg type, regardless of anatomic location.

FISH analysis  shows translocations of myc, Bcl-6 and immunoglobulin H genes

What is the treatment for cutaneous B-cell lymphoma?

The rarity of PCBCLs and lack of comparative prospective, randomised studies limits the choice of therapy as most treatments are based on data from small retrospective studies. The European Organisation for Research and Treatment of Cancer Cutaneous Lymphoma Group (EORTC-CLG) and the International Society for Cutaneous Lymphoma (ISCL) have uniform recommendations on treating the three main types of PCBCL. Treatment  is also influenced by whether the lesion is single or limited to a single site.

Primary cutaneous follicle centre lymphoma

Without any treatment, PCFCL lesions may be stable, gradually enlarge, or rarely, regress. The histological growth pattern does not influence survival or treatment choice.

  • If PCFCL presents with a solitary lesion or is limited to a single site, treatment involves radiation therapy or surgery. Skin recurrences are common and often are outside the treated site but these do not affect prognosis.
  • Patient with multiple lesions can be observed or given radiation, topical agents, cryotherapy, intralesional steroids or systemic therapy. Where disseminated skin lesions or large tumours occur, chemotherapy may be required such as ie, CHOP or R-CHOP.
  • Immune-based therapies like rituximab, interferon and imiquimod are being explored.

Primary cutaneous marginal zone B-cell lymphoma

The recommended therapies for PCMZL are similar to PCFCL.

  • Radiotherapy is highly effective and potentially curative for solitary or few contiguous lesions, but the relapse rates of PCMZL can be higher than PCFCL.
  • Primary surgical excision can be effective for solitary or localized PCMZL.
  • Local treatments include topical corticosteroids, intralesional steroidstopical nitrogen mustard, intralesional rituximab and cryotherapy.
  • Multifocal skin lesions are treated with chemotherapy agents such as chlorambucil, interferon alpha and anti-CD20 antibody (rituximab).
  • PCMZL associated with Borrelia burdorferi infection may be treated with antibiotics
  • Rarely, disseminated skin lesions are treated with chemotherapy (eg, CHOP).

Primary cutaneous large B-cell lymphoma, leg type

Localised or solitary leg-type B-cell lymphoma is usually are treated with local radiotherapy alone or in conjunction with R-CHOP.

Generalised PCDLBCL-LT can be treated with R-CHOP and/or local radiotherapy. Response rates are high but relapse rates are  > 58% Around 30%  develop extracutaneous disease.

Trials are assessing the efficacy of biological agents like ofatumumab, lumilixumab, dacetuzumab and intralesional TG1042 in the treatment of PCDLBCL-LT.

What is the outcome for cutaneous B-cell lymphoma?

Primary cutaneous follicle centre lymphoma

  • Solitary or multifocal PCFCL may enlarge slowly or spontaneously resolve.
  • Recurrence occurs in about 46.5% of patients.
  • 5-year survival rates are around 95%
  • Dissemination to extracutaneous sites occurs in about 5–10% of cases.
  • PCFCL on the leg has a poorer prognosis with 41% survival rate within 5-years.

Primary cutaneous marginal zone B-cell lymphoma

  • 5-year disease-specific survival of PCMZL is up to 99%.
  • Occasionally, early spontaneous resolution of PCMZL can occur
  • The disease can recur inabout 40% of patients, especially if multiple sites are involved.
  • It is rare for PCMZL to metastasise to extra-cutaneous sites.

Very rarely, PCMZL can transform into DLBCL.

Primary cutaneous large B-cell lymphoma, leg type

  • PCDLBCL-LT frequently disseminates to extracutaneous sites and has poor prognosis in spite of aggressive therapy.
  •  5-year survival rates are approximately 50%.
  • In a large multi-centre French study, leg tumours had a 3-year disease-specific survival rate of 43% versus 77% in patients with PCDLBCL not involving the leg.
  • 3-year disease-specific survival of patients with multiple skin lesions was 39% compared to 77% in those with single lesions.

Primary cutaneous diffuse large B-cell lymphoma, other 

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Related information



  • Suarez AL, Querfeld C, Horwitz S, Pulitzer M, Moskowitz A, Myskowski PL. Primary cutaneous B-cell lymphomas: Part I Clinical features, diagnosis and classification. J Am Acad Dermatol 2013; 69(3): 329.e1-13. Available at:
  • Suarez AL, Querfeld C, Horwitz S, Pulitzer M, Moskowitz A, Myskowski PL. Primary cutaneous B-cell lymphomas: Part II Therapy and Future Directions. J Am Acad Dermatol 2013; 69(3): 343.e1-11. Available at:

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