Erdheim-Chester disease with predominant cerebellar manifestations: a case report with literature review.

Erdheim-Chester disease (ECD) is a rare disorder marked by systemic infiltration of lipid-laden histiocytes, often due to BRAFV600E mutations. We present the case of a middle-aged male with progressive cerebellar dysfunction and obstructive hydrocephalus. MRI revealed a non-enhancing bilateral cerebellar mass with effacement of the fourth ventricle. The diagnosis was confirmed by histopathology showing CD68 and CD163 positivity and CD1a negativity. Initial management included an external ventricular drain, with systemic evaluation and molecular testing to guide further treatment, emphasizing the importance of multimodal diagnostics and tailored therapy in improving outcomes.