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

Abstract 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. Pathology 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 EBER-positive 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.