Case of primary central nervous system lymphoma after open head injury]

A 65-year-old man had suffered contusion of the left frontal lobe of the brain with a skull base fracture, pneumocephalus, and cerebrospinal fluid (CSF) leakage. He was treated with ceftriaxone 4 g/day for 14 days, but after 1 month he developed multiple cranial nerve palsies (bilateral III-X). CSF contained increased levels of protein (96 mg/dl) and mononuclear cells (72 cells/mm³), and low glucose levels (40 mg/dl, blood sugar 120 mg/dl), but no malignant cells were detected. Magnetic resonance imaging (MRI) disclosed swelling in multiple cranial nerves with Gd enhancement. Anti-biotic and antifungal therapy remitted the facial, glossopharyngeal, and vagus nerve palsies and reduced the Gd-enhancement lesion, as detected by MRI. However, the eyes were bilaterally dilated and medially fixed, and hearing impairments persisted. After 3 months, follow-up MRIs revealed the presence of Gd-enhanced small masses at the ventral pontine base, medulla, and cervicomedullary junctions despite a lack of change in neurological symptoms. Those lesions subsided favorably upon treatment with intravenous and oral corticosteroids. After 1 year and 9 months, Gd-enhanced small cystic masses appeared on the medulla and cerebellum. An open biopsy of the cerebellar tonsillar lesions revealed diffuse large B cell lymphoma. Although the development of primary central nervous system lymphoma after open head injury and infection has not been reported to date, central nervous system lymphomas may mimic diverse neurological diseases. Brain biopsy remains the only definitive diagnosis, and thus should be pursued if blood and CSF markers appear normal.