Clinical and imaging characteristics of corticosteroid-responsive chronic lymphocytic inflammation with Pontine perivascular enhancement syndrome (CLIPPERS): an analysis of 9 cases.

Purpose: This study aimed to elucidate the clinical and radiological profiles of Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS), targeting an enhanced comprehension and more efficient diagnosis of this rare disorder among medical professionals.

Methods: We conducted a retrospective cohort study, encompassing a detailed analysis of clinical and imaging data from nine CLIPPERS patients diagnosed between 2016 and 2023 at Xuzhou Medical University Affiliated Hospital and Beijing Xuanwu Hospital.

Results: Our study included nine patients, comprising seven males and two females, with ages varying from 9 to 79 years.The clinical spectrum was broad, including lower limb weakness (5 cases), unsteady gait (6), lower limb numbness (2), visual impairments (4), dizziness and headaches (5), cognitive impairments (2), facial sensory abnormalities (2), language disturbances (4), nausea and vomiting (1), limb twitching (1), fever (1), and chest and abdominal discomfort (1).Brain MRI scans uniformly disclosed multifocal lesions with slightly prolonged T1 and pronounced T2 signal characteristics in the brainstem, notably in the pons, as well as in bilateral thalami, cerebellum, and basal ganglia. High signal intensity on FLAIR sequences and variable signal intensity on DWI sequences were observed, with post-contrast imaging exhibiting the pathognomonic punctate and curvilinear 'pepper-like' enhancement. Cervical spinal cord MRIs from two patients mirrored this enhancement pattern. Pathological examination via biopsy in two cases-one of brain tissue and one of spinal cord tissue-demonstrated perivascular infiltration of CD3 + T lymphocytes, accompanied by CD20+, CD5+, and CD68 + cell infiltrations. A favorable response to corticosteroid therapy was observed across all patients, with marked amelioration in clinical symptoms and radiological findings. Remarkably, one patient, diagnosed with classical Hodgkin's lymphoma two years post-onset, showed no signs of recurrence on subsequent PET-CT scans following standard chemotherapy. The remaining patients were either on steroid maintenance therapy or received a combination of steroids and immunosuppressants, with symptomatic improvement noted in all.

Conclusions: CLIPPERS syndrome is distinguished by its characteristic MRI features and demonstrates a robust response to corticosteroid therapy, leading to rapid clinical and radiological improvement. In scenarios with ambiguous diagnosis, pathological tissue biopsy offers essential confirmation.