Primary CNS Lymphoma of Diffuse B cells in a Patient with Neurofibromatosis Type 1: A Case Report.

Abstract

Objective: To describe the case of a patient diagnosed with Neurofibromatosis Type 1 (NF1), who developed her first neoplastic lesion as Primary Central Nervous System Lymphoma (PCNSL). To our knowledge, this is the third case of PCNSL in the context of NF1.
 Background: PCNSL represents 1% of non-Hodgkin extranodal Lymphomas, and 3% of CNS tumors. Diffuse Large B-Cell Lymphoma accounts for 30-40% of the cases, commonly found in the encephalus, spinal cord, leptomeninges, or the eye. Predominant malignant tumors in NF1 are gliomas and Malignant Peripheral Nerve Sheath Tumor (MPNST).
 Methods: A 53-year-old Mexican female, with a history of NF1, arrived at the emergency department with left-side subacute progressive numbness and weakness. Left hemiplegia. MRI showed a ring-enhancing lesion in the right central lobe and a lesion in the subcutaneous tissue. Additionally, the patient underwent a full body 18-FDG PET scan, which reported activity only in the CNS. 
 Results: Lesion-centered craniectomy and surgical evacuation were performed. Histopathological examination revealed lymphoid lineage cells, CD20, PAX-5, and Ki-67 were positive for neoplastic cells, confirming the diagnosis of PCNSL. At the 6-months follow-up visit, strength improved significantly, and the follow-up MRI did not show residual mass. 
 Conclusions: It is necessary to study the prevalence of LPSNC in these patients, as well as the relative risk, and to develop guidelines for its best approach. We believe that the real incidence of the disease is underestimated, since the genetic and pathophysiological mechanisms that promote its origin still need to be clarified.