Primary central nervous system ALK-positive anaplastic large cell lymphoma in an adult: A rare case report

RATIONALE: Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin lymphoma. It mostly invades lymph nodes with extranodal involvement observed in the soft tissue, bone, and skin. PATIENT CONCERNS: We report a 34-year-old Chinese male patient who presented with headache, diplopia, and vomit. Cerebrospinal fluid (CSF) analysis via lumbar puncture showed elevated CSF pressure, elevated CSF protein concentrations, decreased CSF glucose and chloride concentration significantly, and pleocytosis of 68 to 350 × 10(6)/L, in which lymphocytes and monocytes were predominant. These changes could be suggestive of tuberculous (TB) meningitis. Enhanced magnetic resonance imaging of spinal cord delineated multiple enhancing nodules in spinal cord, cauda equina, and cristae membrane, and multiple abnormal enhancing lesions in bilateral lumbar intervertebral foramen. DIAGNOSES: Spinal dura mater biopsy and paraffin pathology examination revealed anaplastic lymphoma kinase positive ALCL. INTERVENTIONS: High-dose methotrexate, cytosine arabinoside craniospinal, and radiotherapy. OUTCOMES: Last follow-up on September 22, 2015 showed no evidence of tumor recurrence and the lower extremity muscle strength recovered to 4/5. LESSONS: ALCL of primary central nervous system is an exceedingly rare tumor, which is usually misdiagnosed as meningitis (especially TB meningitis) according to clinical manifestation and laboratory examination. Thus closely monitoring patient's conditions and timely adjusting therapeutic regimen during treatment are necessary.