Despite Novelty, Fluid Overload–Associated LBCL Has Distinguishing Features

Fluid overload-associated large B-cell lymphoma (FO-LBCL) is a newly described hematolymphoid tumor, and a new case report and review outlines some of the key features clinicians can use to diagnose it.

FO-LBCL was first described in the fifth edition of the World Health Organization’s Classification of Hematolymphoid Tumors, explained the present study’s authors

Writing in the journal Hematology Reports, the investigators said some patients have malignant lymphomas with symptoms of serous effusions in body cavities but without any tumor mass.

“Historically, this presentation has been associated with primary effusion lymphoma (PEL), a human herpesvirus 8 (HHV8)–positive B-cell lymphoma with a predilection for patients that are immunocompromised, typically in the setting of HIV infection,” they wrote.

Yet, some cases do not easily align with a PEL diagnosis because they are negative for HHV8 and occur in patients who are not immunocompromised. In the fourth edition of the WHO’s classification manual, FO-LBCL was categorized as large B-cell lymphoma with chronic inflammation. However, the investigators said the specific clinicopathological presentation of FO-LBCL prompted the agency to give the cancer type its own label.

In this new report, they detail the case of an 82-year-old man who was referred to their hospital due to shortness of breath from recurrent pleural effusion. He had an extensive history of medical issues, including atrial fibrillation, atrial flutter, status post ablation, essential hypertension, hyperlipidemia, and type 2 diabetes. The patient said he had no cough, chest pain, or fever. His surgical history included coronary artery bypass graft surgery and coronary angioplasty with stent placement. His physicians decided to perform right video-assisted thoracoscopy and a right pleural biopsy.

“Histopathological examination of the pleural biopsy revealed dense fibrous tissue, chronic inflammation, lymphoid aggregates, and granulation tissue, with no evidence of lymphoma,” the authors said.

However, cytology of the right pleural fluid showed large lymphoid cells that were positive for CD45, CD20, PAX-5, MUM-1, BCL2, BCL6, and MYC protein, but the cells were negative for CD3, CD10, CD138, and HHV-8 by immunohistochemistry. The patient was also negative for Epstein-Barr virus (EBV).

“In the absence of any evidence of lymphoma elsewhere and since the only site of disease was the pleural cavity, the diagnosis of FO-LBCL was made,” they wrote.

The patient was given instructions for physical therapy and wound care and was referred to a hematology-oncologist, the authors said.

One of the first clues that a case might be FO-LBCL and not PEL, the authors noted, is the patient’s age. PEL tends to appear in patients who are young or of middle-age and who are immunocompromised. The majority of PEL cases are men, they noted. FO-LBCL is also more common in men, but only slightly. In addition, it is seen most in older, immunocompetent patients. Unlike PEL, FO-LBCL is not associated with HHV8 infection, they said, and most cases are negative for EBV.

“Most cases are typically of non–germinal center B-cell like subtype,” they said. “Pan B-cell markers are always positive, which helps distinguish it from PEL.”

Meanwhile, the lack of lymph node involvement is a key factor in distinguishing cases of LO-LBCL from diffuse large B-cell lymphoma (DLBCL), they noted.

In general, the investigators said patients with FO-LBCL have a favorable prognosis, although it is largely affected by comorbidities. By contrast, patients with PEL have a median survival of less than 6 months, they noted.

Still, the sutdy investigators said there is much to be learned about FO-LBCL, which is one of the reasons they published their case report.

“The clinical behavior of this rare type of lymphoma is obscure,” they said, “so a more extensive clinicopathological analysis of additional cases is needed to better understand this disease.”

Reference

Bahmad HF, Gomez AS, Deb A, Safdie FM, Sriganeshan V. Fluid overload-associated large b-cell lymphoma: a case report and review of literature. Hematol Rep. 2023;15(3):411-420. doi:10.3390/hematolrep15030042