Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement not Responsive to Steroids – Management Decisions in a Situation of Diagnostic Uncertainty (P2.2-047)

Objective: To present a case of ‘non-CLIPPERS’ and discuss the diagnostic and management uncertainties in these cases. Background: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a central nervous system inflammatory syndrome predominantly affecting the brainstem, but with manifestations known throughout the brain and spine. An increasing number of patients with reported CLIPPERS have been described in recent years, but many fail to meet the strict diagnostic criteria. Even within the cohort reported with the new diagnostic criteria, one-third of patients did not meet criteria (Tobin et al, 2017). 2/3s of the ‘non-CLIPPERS’ patients lacked a formal diagnosis, and there is limited guidance on management of these patients. Design/Methods: NA Results: A 59-year-old man presented with fatigue, dizziness, left facial numbness, and tinnitus evolving over months. Exam demonstrated limited left lateral gaze, hyperreflexia, and asymmetric postural tremor. MRI brain showed an area of increased T2 signal in the left middle cerebellar peduncle (MCP) with patchy nodular enhancement. Extensive laboratory testing for autoimmune, infectious, and neoplastic entities failed to identify a cause. Biopsy of the left MCP demonstrated an intense perivascular inflammatory infiltrate of CD3/CD4+ T-lymphocytes, without evidence of necrotizing vasculitis or demyelination. A presumptive diagnosis of CLIPPERS was made. However, the patient failed to respond to corticosteroid treatment, with both clinical and radiographic deterioration, inconsistent with a CLIPPERS diagnosis. The patient was subsequently started on oral methotrexate with good effect. Conclusions: The diagnosis of CLIPPERS is challenging. In an already rare disorder, similar presentations that do not meet diagnostic criteria present a management quandary, as most non-CLIPPERs patients will lack a formal diagnosis. In patients with similar radiographic and pathological features, the approach to management should be similar, with therapies targeting the inflammatory T-cell infiltrate. A lack of response to steroids does not necessarily predict an alternative etiology. Disclosure: Dr. Sengul has nothing to disclose. Dr. Gyang has nothing to disclose. Dr. Carlson has nothing to disclose.