Prognostic significance of immunohistochemical markers in Primary CNS lymphomas

Introduction: Primary CNS lymphoma (PCNSL) is a rare form of extra nodal Non-Hodgkin Lymphoma that is typically con?ned to the brain, spinal cord, lepto meninges and eyes. We studied the clinico pathological features of PCNSLs, immuno histochemical (IHC) markers expressed and the association of morphological features & IHC markers with clinical outcome. Materials and Methods: 30 cases of primary CNS lymphomas were studied. 25 cases were diffuse large B cell lymphomas, which were sub classified using Hans algorithm into GCB and non-GCB. The IHC markers done were CD20, CD3, BCL2, BCL6, MUM-1, CD10 and c-myc. Mean proliferation index Ki was 80%. Follow up and survival data was collected and the association of each IHC marker and subtype with prognosis was assessed. Conclusion: PCNSL forms around 2% of all lymphomas as well as primary CNS tumours. Non GCB type is more common (72%). Mean overall survival was 9.7 months. Ki-67 index of 80% or more is the only independent variable of prognostic significance. None of the other IHC markers or sub typing had any influence on the outcome.   Keywords: Primary CNS lymphoma, IHC, Prognosis, GCBsubtype, Ki 67 index