LabMed

Lymphomatoid Granulomatosis (LYG)

At a Glance

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus (EBV)-associated, systemic, angiodestructive B cell lymphoma that frequently involves the lungs. Lymphomatoid granulomatosis occurs twice as frequently in males than females, is most common in the fifth to sixth decades, and frequently occurs in patients with immune system dysfunction, including HIV-1 infection, chronic viral hepatitis, Sjögren syndrome, rheumatoid arthritis, and post kidney transplantation. In addition to pulmonary involvement marked by cough, dyspnea, and occasionally hemoptysis, some patients exhibit nervous system and/or skin involvement. Clinically apparent involvement of other organ systems (e.g., kidney, liver) is less frequent.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

There are no characteristic or specific laboratory abnormalities found in LYG patients. Pulmonary imaging studies are usually abnormal but, again, nonspecific. Nodular infiltrates or masses are observed in 80-100% of patients. Definitive diagnosis of LYG, typically, requires either an open wedge lung biopsy or a thoracoscopic video-directed biopsy of affected lung tissue. Transbronchial biopsies are believed to be of low diagnostic yield.

Lesions are characterized by a polymorphic, vessel wall-associated, infiltrate of small lymphocytes, plasma cells, and large atypical mononuclear cells. Granulomatous collections of cells around areas of necrosis can be prominent. Immunophenotyping of lesional cells reveals both B and T lymphocytes. Epstein-Barr virus RNA is found in monoclonal (occasionally oligoclonal) proliferations of B lymphocytes, whereas the T lymphocytes are polyclonal.

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?

Diagnostic tissue is required to make an LYG diagnosis. Transbronchial biopsies are often inadequate.

What Lab Results Are Absolutely Confirmatory?

Appropriate histologic findings coupled with EBV RNA and monoclonal/oligoclonal B lymphocyte proliferation are diagnostic.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

A minority of patients with LYG exhibit atypical findings with pulmonary imaging studies. Massive nodules, pleural effusions, pneumonitis, and cavitary nodules can be seen. Patients with hemoptysis are more likely to have cavitary nodules. Definitive diagnosis is still based on biopsy and the demonstration of histologic findings described.

Diagnosis of LYG can sometimes be made based on biopsy of more accessible tissues, such as skin.

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