Polymorphic central nervous system (CNS) immune deficiency/dysregulation-associated lymphoproliferative disorders show a uniquely aggressive clinicopathologic profile compared to their extra-CNS counterparts.

BACKGROUND

Primary central nervous system immunodeficiency/dysregulation-associated lymphoproliferative disorders (PCNS-IDD-LPDs) are a rare and heterogeneous group of lymphoid lesions that arise within the CNS of immune compromised patients. Among PCNS-IDD-LPDs, monomorphic IDD-LPDs are relatively well studied; however, data regarding PCNS polymorphic IDD-LPDs is very limited. It remains unclear whether polymorphic PCNS IDD-LPDs follow a similarly indolent clinical course as observed in their systemic polymorphic counterparts, or whether the unique immune microenvironment of the CNS imparts a more aggressive disease biology.

METHODS

In this study, we compared the clinical, pathologic, and survival profile of PCNS polymorphic IDD-LPDs (N = 15) with extra-CNS polymorphic IDD-LPDs (N = 21) as well as PCNS monomorphic IDD-LPDs (N = 12).

RESULTS

Compared to extra-CNS polymorphic IDD-LPDs, patients with PCNS polymorphic IDD-LPDs showed a significantly stronger association with kidney transplants, longer latency, worse performance status, more frequent monoclonal populations and necrosis, and a greater need for aggressive chemoimmunotherapy in addition to reduction in immunosuppression and/or rituximab. The overall survival (OS) of PCNS polymorphic IDD-LPDs was significantly inferior to that of extra CNS polymorphic IDD-LPDs (median survival: 7.1 years vs. not reached; log-rank p = 0.023) and not significantly different from PCNS monomorphic IDD-LPDs (median survival: 7.1 vs. 3.6 years; log-rank p = 0.852).

CONCLUSION

We conclude that PCNS polymorphic IDD-LPDs have a uniquely aggressive clinicopathologic and prognostic profile compared to their systemic counterparts and are comparable to their monomorphic PCNS counterparts. CNS localization supersedes the histological subtype as the primary determinant of disease biology in IDD-LPDs, likely ascribed to the immune sanctuary status of the CNS.