[RA-06] Lymphohistiocytic pattern of ALK-positive anaplastic large cell lymphoma in the brain mimicking inflammatory processes

Narittee Sukswai

Department of Pathology, Cholalongkorn University, Bangkok, Thailand

ALK-positive anaplastic large cell lymphoma (ALCL) constitutes 3% of non-Hodgkin lymphoma in adolts. Brain involvement is rarely noted. A systematic review of primary ALCL of the central nervous system is found only 36 globally reported cases with noted clinical course, adequate radiological imaging and ALK status. Only 28 of the cases show ALK positivity. Regarding microscopic findings, most of the cases of ALCL (> 60%) is harboured common pattern, exhibiting proliferation of large anaplastic cells that tends to evade sinuses and paracortex of the lymph node. Only a small number of cases (approximately 10%) shows lymphohistiocytic pattern. We hereby present a case of ALK-positive ALCL arranged in lymphohistocytic pattern mimicking inflammation involving the brain. Acknowledgment of such cases may help with the diagnosis of the extremely rare case and lead to the correct management of the patient.

Keywords: ALK status; anaplastic large cell lymphoma; central nervous system