Subdural Hematoma During Lorlatinib-Induced Regression of Leptomeningeal Carcinomatosis with Suspected Dural Involvement in ALK-Positive Lung Adenocarcinoma.

Lorlatinib, a central nervous system (CNS)-penetrant anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor, is effective in treating leptomeningeal carcinomatosis. A woman in her 30s with ALK-positive lung adenocarcinoma and leptomeningeal carcinomatosis developed an asymptomatic subdural hematoma (SDH) 7 weeks after starting lorlatinib, coinciding with the regression of leptomeningeal lesions. The posterior extent of the SDH appeared to be partially contiguous with the focal dural enhancement observed before treatment. Lorlatinib was continued under multidisciplinary supervision. The hematoma resolved without surgery and did not recur during the 6 years of treatment. SDH may occur during the rapid regression of leptomeningeal disease with suspected dural involvement under CNS-penetrant ALK inhibitor therapy.