title: Melanoma Brain Metastasis Pseudoprogression after Pembrolizumab Treatment.
abstract: The role of immunotherapy in treatment of brain metastases is unknown because most trials exclude patients with active brain lesions. As new immunomodulating agents gain approval for many malignancies, it is important to know if they have unique effects in the central nervous system (CNS). Here, we present a case of a patient with progressing brain metastases treated with a single cycle of pembrolizumab, who presented with mental status changes 11 days thereafter. MRI of the brain showed enlargement of CNS lesions with intense central enhancement and diffuse perilesional edema. Histologic evaluation of a resected lesion revealed isolated clusters of tumor cells surrounded by reactive astrocytosis, scattered inflammatory cells, and an abundance of microglial cells. Given the increasing use of immune checkpoint inhibitors in patients with brain metastases from melanoma and other diseases, recognition of pseudoprogression and management with immune suppression are essential.
authors.affiliation: Department of Medicine, Section of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Justine V
authors.initials: JV
authors.lastname: Cohen
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Ahmed K
authors.initials: AK
authors.lastname: Alomari
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Vortmeyer
authors.affiliation: Department of Medicine, Section of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Lucia B
authors.initials: LB
authors.lastname: Jilaveanu
authors.affiliation: Department of Medicine, Section of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Goldberg
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Amit
authors.initials: A
authors.lastname: Mahajan
authors.affiliation: Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Chiang
authors.affiliation: Department of Medicine, Section of Medical Oncology, Yale University School of Medicine, New Haven, Connecticut. Harriet.Kluger@Yale.edu.
authors.forename: Harriet M
authors.initials: HM
authors.lastname: Kluger
mesh_terms: D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000556:secondary; D018450:Disease Progression; D005260:Female; D006801:Humans; D008545:Melanoma / Q000175:diagnosis* / Q000188:drug therapy / Q000556:secondary; D008875:Middle Aged; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; C582435:pembrolizumab