Diffuse Large B-cell Lymphoma, NOS, Immunoblastic

Diffuse Large B-cell Lymphoma, NOS, Immunoblastic

Francisco Vega, MD, PhD

DLBCL-IB shows large immunoblasts compared with the size of histiocyte nuclei image. Immunoblasts have a single, central, prominent nucleolus.

PET/CT scan of a patient with DLBCL-IB shows bulky lymphoma of the left neck image, right paratracheal space, retroperitoneum, spleen image, and vertebral bodies image.



  • Diffuse large B-cell lymphoma, immunoblastic variant (DLBCL-IB)


  • Immunoblastic lymphoma

  • Immunoblastic sarcoma


  • Diffuse proliferation of large neoplastic B cells with immunoblastic cytologic features

    • By definition, immunoblasts must be > 90% of all cells

  • Immunoblast

    • Large lymphocyte with centrally located nucleolus and moderate basophilic cytoplasm

  • DLBCL-IB variant superseded by specific types of DLBCL as defined in WHO classification



  • Incidence

    • Predominantly disease of older adults

      • Children and young adults can be affected


  • Enlarging mass in nodal or extranodal sites

  • Gastrointestinal tract is frequent extranodal site

  • ˜ 1/3 of patients have stage IV disease

  • Bone marrow involvement less frequent than in patients with low-grade B-cell lymphomas

  • Frequent B symptoms (fever, night sweats, or weight loss)


  • R-CHOP regimen (rituximab + cyclophosphamide, doxorubicin, vincristine, and prednisone)


  • Some studies have identified immunoblastic variant as being clinically more aggressive than centroblastic variant

  • 5-year overall survival for patients with DLBCL ranges from 25-75% depending on prognostic factors present at diagnosis


Histologic Features

  • Diffuse growth pattern

    • Irrespective of location, DLBCL-IB diffusely replaces normal architecture

  • Immunoblastic morphology

  • Plasmacytoid differentiation is common



  • Pan-B cell antigens(+)

    • CD20 can be dim, attributable to plasmacytoid differentiation

  • CD10(+), Bcl-6(+), LM02(+), HGAL(+) in subset

  • MUM1(+) in cases with plasmacytoid differentiation

  • FoxP1(+/-), Bcl-2(+/-), CD30(-/+), and usually weak and partial

  • Proliferation fraction (Ki-67) is usually high

  • Algorithms proposed to identify GC and non-GC types

    • Hans et al

    • Choi et al


DLBCL, Centroblastic Variant

  • Centroblastic and immunoblastic variants can be difficult to distinguish reliably

    • Justifies their inclusion into DLBCL as variants

  • By definition, at least a significant number (> 10%) of neoplastic cells are centroblasts

  • Subtle morphologic features supporting centroblastic variant

    • 2-3 nucleoli with 1 central and 1-2 apposed to nuclear membrane

    • Absence of plasmacytoid differentiation

    • Presence of small and large cleaved cells

    • Residual follicular pattern

DLBCL, Anaplastic Variant

  • Large neoplastic cells with bizarre morphology; may resemble Hodgkin &/or Reed-Sternberg cells

  • These neoplasms may have intrasinusoidal growth pattern

  • CD30 often positive

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Diffuse Large B-cell Lymphoma, NOS, Immunoblastic
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