Primary CNS lymphoma: findings outside the brain.

In addition to the brain parenchyma and the leptomeninges, primary central nervous system lymphoma (PCNSL) can involve the posterior parts of the eye with ocular lymphoma in up to 20% of patients and lead to systemic dissemination of lymphoma in 7-8% of patients. Ocular lymphoma is diagnosed by slit lamp examination and requires treatment by ocular irradiation. However, the clinical significance of systemic dissemination, which occurs mainly in the end stage of the disease, appears to be disputable. Extensive systemic staging at the time of initial presentation proved to be unrewarding in the vast majority of studies. So far, only 10 patients have been reported with occult systemic lymphoma at time of initial presentation, and systemic lymphoma determined the course of the disease in none of them. Thus, initial staging procedures for patients with biopsy-confirmed PCNSL can be restricted to regular blood tests, including HIV testing, and slit lamp examination of the eye.