To report an atypical case of Acute Lymphoblastic Leukemia (ALL) with central nervous system (CNS) involvement recurrence with clinical and radiological findings mimicking cerebellitis

The specific mechanism of involvement of the CNS by acute leukemic cells is incompletely understood. CNS involvement in ALL are known to involve meninges, subarachnoid space and rarely, brain parenchyma, mimicking other CNS pathologies such as cerebellitis; which tends to be a self-limited condition treated with corticosteroid therapy for symptomatic relief. However, in contrast to cerebellitis, ALL with CNS involvement is not self-limited and requires other medical interventions such as chemotherapy or radiation.

We report the case of a 47 y/o Hispanic male patient with history of  ALL  with previous CNS involvement  in remission that  presented to Emergency Department due to acute onset occipital headache, nausea, vomiting, poor coordination, vertigo and imbalance. Physical examination was remarkable for dysmetria, dysdiadochokinesia and horizontal nystagmus. No fever, nuchal rigidity or decreased alertness. Workup including basic labs and CSF studies ruled out infectious etiology. Brain MRI was remarkable for diffuse abnormal signal intensity of cerebellum and bilateral, symmetrical cerebellar swelling suggestive of an acute cerebellitis. No pachymeningeal, parenchymal or leptomeningeal enhancement upon contrast administration were identified, making CNS malignancy less likely based on radiographic findings. CSF analysis including cytology and flow cytometry confirmed presence of malignant cells compatible with ALL recurrence with CNS involvement.

Here we present a patient with recurrence of ALL in the CNS with clinical and imaging findings mimicking cerebellitis secondary to cerebellar infiltration. With this case we emphasize the importance of screening for neoplastic recurrence within the CNS in a patient with history of ALL and new neurological symptoms, to avoid delay in treatment and prevent further neurological decline.