Primary Cutaneous Diffuse Large B-cell Lymphoma, Leg Type

Primary Cutaneous Diffuse Large B-cell Lymphoma, Leg Type

Sa A. Wang, MD

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT). This field shows a diffuse infiltrate replacing the dermis with sparing of the epidermis image.

The lymphoma cells in PCDLBCL-LT are large and strikingly round with centrally located nucleoli (immunoblasts).



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


  • Primary cutaneous large B-cell lymphoma, leg type

  • Primary cutaneous diffuse large B-cell lymphoma


  • Primary cutaneous diffuse large B-cell lymphoma composed exclusively of large transformed B cells

    • Often occurs in lower leg(s) but can arise at other skin sites


Cell of Origin

  • Peripheral B cell of post-germinal center cell origin

    • Immunophenotype: IRF-4/MUM1(+), FOXP1(+)

    • High frequency of somatic mutations of IgH variable (V)-region genes

Possible Role of Antigen Selection

  • Preferential use of certain IgH V gene segments

    • Suggests that antigen stimulation may be involved in pathogenesis

Role of Molecular Abnormalities

  • Number of genetic rearrangements and deletions reported

  • No abnormality consistently present



  • Incidence

    • Rare

      • 4% of all cutaneous lymphomas

      • 20% of primary cutaneous B-cell lymphomas

  • Age

    • Elderly patients; median age: 7th decade

  • Gender

    • More common in women

      • Male to female ratio: 1:1.6; as high as 1:4 in some studies


  • Most cases arise in skin of lower leg; 1 or both legs

    • ˜ 85% of all cases

  • Subset of cases arise in skin of other sites (trunk, arms, head and neck)

    • ˜ 15% of cases

    • Similar morphologic and immunophenotypic characteristics

  • Single or multiple lesions at time of presentation

    • Some patients have dissemination at initial diagnosis


  • Red or blue-red lesions on skin

    • Plaque, verrucous plaques, or deep plaques

    • Nodular, tumoral lesions

    • Often associated with ulcer

    • Multiple lesions are common

  • B symptoms in 10-20% of patients


  • Anthracycline-containing systemic chemotherapy plus rituximab (R-CHOP)

  • Radiotherapy has role for localized lesions in elderly patients


  • Relapse is common

  • 40-50% 5-year survival rate

    • Factors adversely correlated with prognosis

      • Older age

      • Multiple lesions at presentation

      • Inactivation of CDKN2A

    • Factors not correlated with prognosis

      • Duration of lesions before diagnosis

      • Gender, B symptoms, performance status or serum lactate dehydrogenase level

      • Bcl-2 or IRF-4/MUM1 expression


Histologic Features

  • Diffuse pattern of involvement in dermis

    • Infiltrate can be deep

  • Cohesive, monotonous sheets of large cells

    • Centroblasts or immunoblasts

    • Often very round nuclei

  • Mitotic figures numerous

  • Few small reactive T cells in background

  • No centrocytes (or small B cells) present

  • No epidermotropism



  • Pan-B-cell antigens(+)

  • Cytoplasmic IgM(+), IgD(+/−)

  • Bcl-2(+), IRF-4/MUM1(+), FOXP1(+)

  • Bcl-6(+), CD10(−)

  • No follicular dendritic cell (FDC) meshworks

    • CD21(−), CD23(−), CD35(−)

  • T-cell antigens(−), LMP1(−), HHV8(−)

In Situ Hybridization

  • FISH often shows rearrangements of MYC, BCL-6, or IgH genes

  • No evidence of IgH-BCL-2/t(14;18) or BCL-2 rearrangements

  • EBER(−)

Array CGH

  • Amplification of 18q21.31-33 involving BCL-2 and MALT1 genes

Molecular Genetics

  • Monoclonal IgH gene rearrangements

  • No evidence of IgH-BCL-2/t(14;18)

Gene Expression Profiling

  • Profile is consistent with activated B-cell phenotype


Primary Cutaneous Follicle Center Cell Lymphoma (PCFCL)

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Primary Cutaneous Diffuse Large B-cell Lymphoma, Leg Type

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