Leptomeningeal seeding with acute hydrocephalus--unusual central nervous system presentation during chemotherapy in Ki-1-positive anaplastic large-cell lymphoma.

An unusual central nervous system (CNS) manifestation in a 18-year-old male with Ki-1- positive anaplastic large-cell lymphoma is presented. The diagnosis of Ki-1 lymphoma was first confirmed by the distinct pleomorphic morphology, expression of Ki-1 (CD30) antigen on neoplastic cells and the specific chromosome translocation, t(2;5)(p23;q35). Although young age is thought to be a good prognostic factor in this disease, the course in our patient was very aggressive. At presentation, there was already extensive extranodal involvement, with malignant cell found in the pleural cavity and bone marrow. In spite of rapid shrinkage of whole-body lymph nodes and a decrease in malignant pleural effusion soon after starting chemotherapy, headaches and vomiting ensued in the following days. A computerized tomography scan of the brain showed poor corticomedullary differentiation without definite mass lesions, and numerous malignant cells were found in the cerebrospinal fluid (CSF). Although intrathecal methotrexate was given, the patient died following the sudden onset of acute hydrocephalus. CNS involvement in Ki-1 anaplastic large-cell lymphoma is very rare and most cases present as focal mass lesions in the brain parenchyma. Leptomeningeal seeding of the lymphoma cells with acute hydrocephalus contributing directly to death has never been reported. The experience from this case suggests that CNS involvement may present in variable forms in Ki-1 lymphoma and may be an important cause of mortality in young patients, especially those in advanced stages of the disease. Early detection of CNS involvement by CSF investigation or even prophylactic CNS therapy may be mandatory in these patients.