Central nervous system lymphomatoid granulomatosis with polyclonal plasmacytoid cell proliferation: A case report and review of the literature

Background: Lymphomatoid granulomatosis (LYG) is a rare lymphoproliferative disorder, characterized by overproduction of lymphocytes and associated with the Epstein-Barr virus (EBV). Grading of this disorder is based on the number of cells that stain positive for EBV-encoded small nuclear RNA (EBER), and the prognosis of low-grade LYG is generally good. Here, we report an unusual case involving an elderly man with low-grade LYG that rapidly progressed and involved the central nervous system. Case description: An 80-year-old man with no remarkable medical history was referred to our department of dermatology with a 2-month history of a rash on the right side of his back. Pathological examination revealed a mixed cell granuloma. The rash worsened despite treatment, and systemic manifestations appeared over time. He was referred to the department of neurosurgery after a head computed tomography revealed a tumorous lesion centered around the left frontal lobe. Several imaging and laboratory tests and a brain biopsy were performed. The observation of multiple lung, skin, and central nervous system lesions and pathologically noninfectious granuloma formation and angiocentric/angiodestructive lymphocytic infiltration with some EBERpositive cells, led to a diagnosis of grade 1 LYG. An evaluation of the EBV infection and patient immunity revealed that the disease had developed under severe immunosuppression. The patient died 28 days after surgery. Conclusions: If LYG develops in an immunosuppressed state, even if it is low-grade, EBV reactivation may induce significant reactive proliferation of lymphocytes, which may worsen the condition. Thus, prognostication using only EBER-based grading may be inadequate.