The rapid disappearance of primary central nervous system lymphomas (PCNSL) following steroid therapy is common; however, the spontaneous regression of PCNSL without any treatment is extremely rare. This study presented a rare case of PCNSL with preceding pseudotumoral demyelination and no previous steroid treatment, and the pitfalls of PCNSL diagnosis were discussed. A 70-year-old healthy male experienced memory and gait disturbances and showed multiple enhanced lesions with perifocal brain edema in the left cerebrum. The patient had no previous symptoms, no chronic lesions and negative oligoclonal immunoglobulin G bands in the cerebrospinal fluid. Histological examination of a brain biopsy specimen revealed predominantly destructive, demyelinating characteristics with infiltration of several T lymphocytes and foamy macrophages resulting in the diagnosis of multiple sclerosis. The patient received steroid therapy and demonstrated gradual improvement, multiple brain lesions had disappeared from the magnetic resonance imaging (MRI)scan two months after the biopsy. However, three months after the biopsy, the condition of the patient deteriorated. MRI indicated a homogeneous enhanced lesion in the right frontal lobe and a second biopsy was performed. Histological examination during the second biopsy revealed a diffuse large B-cell lymphoma. The patient received whole-brain radiation and steroid therapy, however, succumbed eight months following the initial diagnosis. In the current report a comparison between the our case and six previously reported cases is presented.
Keywords: biopsy; multiple sclerosis; sentinel; steroid; tumefactive.