Normal Pressure hydrocephalus (NPH) is characterized by gait apraxia, urinary incontinence, and dementia. Mixed connective tissue disease (MCTD) is an autoimmune connective tissue disease that has never been reported to cause NPH. Our patient was a 67-year man with a one-year history of gradual worsening gait and balance, urinary urgency with urge incontinence and decreased short-term memory. Previously he was diagnosed with mixed connective tissue disease (MCTD). For him an endoscopic third ventriculostomy (ETV) with brain biopsy was agreed upon. Gliotic brain parenchyma and focal perivascular lymphocytes were noted in the gray matter. There was no lymphocytic infiltration in brain parenchyma. Immunohistochemical stains demonstrated that the mononuclear inflammatory infiltrate was limited to several small cortical blood vessels surrounded by CD3 T-cell lymphocytes with no vessel wall invasion or necrosis. No CD20 B-cell lymphocytes were observed. Viral inclusions, microglial nodules, granulomas, and amyloid deposits in the blood vessels were not noted. In summary, there was no definitive evidence of vasculitis. However, the presence of a perivascular lymphocytic infiltrate around the cortical vessels was “unusual”. Considering this probable co-occurrence suggests the need for a protocol to better evaluate idiopathic NPH in patients with an underlying autoimmune component.