Fibrin-Associated Large B-Cell Lymphoma Arising in the Heart: A Unique Clinicopathologic Entity with Favorable Outcome
Aaron M Gruver, Michael A Huba, Eric D Hsi. Cleveland Clinic, Cleveland, OH
Background: Primary cardiac lymphoma (PCL), a lymphoma confined to the heart or pericardium, comprises 0.5% of extranodal lymphomas and represents <2% of all primary cardiac tumors. PCL often involves myocardium of the right side, and the median overall survival is ∼12 months. We have encountered rare cases of lymphoma in fibrin thrombus associated with heart structures. In order to place these into the context of all cardiac lymphomas, the 30-year experience at a United States cardiovascular referral center was reviewed.
Design: Anatomic pathology archives were queried using natural language searches for all cardiac lymphomas presenting from 1980-2011. Medical records were used to obtain clinical histories. Additional immunohistochemical, in-situ hybridization, and gene rearrangement studies were performed to complement the diagnostic workup on select cases.
Results: 14 cases of lymphoma were identified: 6 PCL (M:F=5, age 55-75) and 8 secondary lymphomas (7 non-Hodgkin & 1 classical Hodgkin). 3 of the PCLs were diffuse large B-cell lymphoma (DLBCL) (2 germinal & 1 non-germinal center B-cell types) and involved myocardium. The other 3 PCL (Males, age 55-75) lacked myocardial invasion and were found within fibrin clot, without evidence of inflammation. These fibrin-associated large B-cell lymphomas (LBCL) presented incidentally in immunocompetent patients and involved either: a prolapsed myxomatous mitral valve, a left atrial thrombus (clinically masquerading as a myxoma), or a thrombus arising in a synthetic aortic root graft. All 3 specimens showed focal involvement by large atypical lymphocytes expressing a non-germinal center B-cell immunophenotype and were monoclonal by immunoglobulin gene rearrangement studies. Two cases were positive for EBV (type III latency) but all lacked HHV8. No systemic disease was present at the time of diagnosis or during follow-up. All 3 patients with fibrin-associated LBCL were alive without disease at last follow-up (8, 16, and 39 months respectively) while 2 of 3 conventional PCL patients were dead at 2 and 8 months, with the third lost to follow-up. Outcome for secondary lymphoma patients: 4 alive, 2 deceased, 2 censored (median follow-up 42 months).
Conclusions: Fibrin-associated LBCL arising in the heart represents a substantial proportion of PCL and may represent a distinct clinicopathologic entity. These lymphomas express a non-germinal center B-cell phenotype and appear to have a favorable prognosis. The EBV type III latency pattern seen in some cases suggests a degree of host immune suppression.
Tuesday, March 20, 2012 1:00 PM
Poster Session IV # 204, Tuesday Afternoon