[A case of lymphocytic hypophysitis initially diagnosed as aseptic meningitis].

The patient was initially diagnosed with aseptic meningitis based on CSF pleocytosis before the correct diagnosis was established.

• The patient was a 57-year-old man presenting with headache and fever
• Initial diagnosis of aseptic meningitis was based on CSF pleocytosis
• The correct diagnosis of lymphocytic hypophysitis was not established at initial presentation

Symptoms worsened approximately one month after initial presentation, with development of lethargy prompting further investigation.

• One month after initial presentation, symptoms became exacerbated
• Lethargy developed as a new symptom
• General blood tests including electrolytes and creatine kinase showed no abnormalities

Brain MRI with gadolinium enhancement revealed enlargement of the entire pituitary gland extending to the stalk.

• MRI showed enlargement of the whole pituitary gland
• The enlargement spread to the pituitary stalk
• Gd-enhancement was used to visualize the abnormality

Hormonal testing revealed pan-hypopituitarism in this patient.

• Pan-hypopituitarism was identified on hormonal testing
• This finding was consistent with lymphocytic hypophysitis affecting the entire pituitary gland
• Hormonal abnormalities were present despite general blood tests showing no abnormalities

Lymphocytic hypophysitis was diagnosed after excluding other conditions known to cause hypophysitis.

• Differential diagnoses ruled out included sarcoidosis, syphilis, tuberculosis, Sjögren syndrome, and systemic lupus erythematosus
• These conditions were excluded as potential causes of hypophysitis
• The diagnosis of lymphocytic hypophysitis was reached by exclusion

Hormone replacement therapy led to amelioration of both symptoms and pituitary gland enlargement.

• Hormone replacement therapy was the treatment administered
• Both clinical symptoms and radiological findings (pituitary enlargement) improved with treatment
• No surgical or immunosuppressive intervention was described as necessary

This case was considered atypical lymphocytic hypophysitis due to the absence of abnormalities in general blood tests, which is important in the differential diagnosis of aseptic meningitis.

• The case was characterized as 'atypical lymphocytic hypophysitis'
• The atypical feature was the lack of abnormalities in general blood tests
• The authors note that absence of general blood test abnormalities is 'essential when considering a differential diagnosis of aseptic meningitis'
• This presentation highlights lymphocytic hypophysitis as a potential mimic of aseptic meningitis