Lymphomatoid Granulomatosis

 Diffuse growth pattern, not scattered cells of lymphomatoid granulomatosis (LYG)


image Not angiocentric, usually no necrosis, and no mixed background infiltrate


• Vasculitis
image Can show similar histologic features to LYG with inflammation of blood vessels and involvement of multiple organ systems

image Usually not EBV(+), vasculitis has nonmonoclonal B cells



image
LYG at Low Power
Low-power view of cutaneous lymphomatoid granulomatosis (LYG) shows an extensive B-cell infiltrate with a perivascular angiodestructive distribution image. The epidermis image is not involved. (Courtesy M. Royer, MD.)


image
LYG Involving Subcutis
LYG diffusely infiltrating into the fat image can mimic a reactive panniculitis. There is angiocentric involvement with tumor cells surrounding and infiltrating blood vessels image.

image
Epstein-Barr Virus Encoded Receptor in LYG
A higher power magnification of the same lesion shows that many of the Epstein-Barr virus (EBV)-encoded receptor (EBER)(+) cells are large in size image and show some nuclear irregularity. The smaller reactive T cells are EBER(-).

image
*IGH* Gene Rearrangement in LYG
PCR test for IGH gene rearrangements shows a dominant monoclonal peak at position 250 image. IGH gene rearrangements are often detected in LYG since it is a B-cell lymphoma.


TERMINOLOGY


Abbreviations




• Lymphomatoid granulomatosis (LYG)


Synonyms




• Angiocentric immunoproliferative lesion


Definitions




• Extranodal Epstein-Barr virus (EBV)-driven mature B-cell lymphoma that is angiocentric
image It is uncertain whether LYG represents unique disease or is part of spectrum of EBV-associated B-cell lymphoproliferative disorders


ETIOLOGY/PATHOGENESIS


Epstein-Barr Virus




• Due to dysregulated immune surveillance of EBV-infected B cells, particularly by CD8(+) T cells

• Type III latency pattern, LMP and EBNA2(+)


Immunodeficiency




• Most have no clearly defined underlying immunodeficiency

• However, some patients have had allogeneic organ transplant, HIV infection, X-linked lymphoproliferative disorder, and Wiskott-Aldrich syndrome


Cytokines




• IP10 and Mig are implicated in pathogenesis of blood vessel damage


CLINICAL ISSUES


Epidemiology




• Age
image Mostly adults, commonly in 6th decade

image Children with immunodeficiency syndromes

• Sex
image M:F > 2.0:1.0


Site




• Most common site is lung; skin is most frequent extrapulmonary site
image For skin lesions, often trunk or limbs, cutaneous nodules often develop after pulmonary disease

image May show any anatomic distribution, but usually spares bone marrow, lymph nodes, and spleen


Presentation




• Most commonly as erythematous subcutaneous and dermal nodules

• Pulmonary symptoms (cough and dyspnea)

Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Lymphomatoid Granulomatosis
Premium Wordpress Themes by UFO Themes
%d bloggers like this: