Paraneoplastic cerebellar degeneration is rare and noteworthy in children. In this 7-year-old, it was documented to have occurred within a year of
ataxia presentation. The instigating
cancer was stage III adrenal
adenocarcinoma, remitted after surgical resection at age 2. When her severe
ataxia progressed,
neuroinflammation was characterized by high cerebrospinal fluid Purkinje cell cytoplasmic antibody type 1 titers,
oligoclonal bands, and neurofilament light chain. The
immunotherapy strategy was to replace IV
methylprednisolone, which lowered Purkinje cell cytoplasmic antibody type 1 titers without clinical improvement, with induction of
adrenocorticotropic hormone/
intravenous immunoglobulin/
rituximab (
ACTH/
IVIG/
rituximab) combination
immunotherapy,
ACTH/
dexamethasone transition, and
intravenous immunoglobulin maintenance. She became self-ambulatory and cerebrospinal fluid inflammatory markers regressed.
Down syndrome predisposed her to a
second cancer, pre-B
acute lymphoblastic leukemia, 4 years later. Despite reversible
cytosine arabinoside-provoked cerebellar toxicity, the
ataxia is stable on monthly
intravenous immunoglobulin without relapse, now 5 years after initial diagnosis. This report illustrates the use of cerebrospinal fluid
biomarkers to detect, target, and monitor
neuroinflammation, and successful combinations of
immunotherapy to better the quality of life.