How useful are serum ACE, IgG4, and antipituitary antibody (APA) levels for diagnosing hypophysitis?
- Sarcoidosis and IgG4-related diseases generally require a tissue sample for diagnosis. A serum or CSF ACE level is a highly specific (95%), but insensitive (25%–76%) marker for neurosarcoidosis.
- Similarly, for IgG4 hypophysitis, elevated serum/CSF concentrations of IgG4 are found in only ≈ 70% of patients. Lastly, investigations of APAs and antihypothalamus antibodies have been studied, but these tests currently have insufficient sensitivities and specificities for diagnostic utility.
- In general, the diagnosis of hypophysitis is difficult as no preoperative laboratory test currently exists.
- In most cases, the diagnosis is suspected/presumed, and definitive diagnosis of hypophysitis, particularly if indicated by progressive disease, is determined through histologic examination of biopsied tissue.
