[An analysis of four cases of misdiagnosed primary lymphocytic hypophysitis].

To improve the differential diagnosis of sellar region mass, 4 cases with sellar mass and misdiagnosed as lymphocytic hypophysitis (LYH) were reviewed retrospectively.The 4 patients (2 male and 2 female) aged 20-60 years old were all presented with symptoms of headache, polydipsia and polyuria.Biochemical studies confirmed the diagnoses of central diabetes insipidus and hypopituitarism.Head MRI scans showed LYH like image for all the cases, and, thus, high dose methylprednisolone pulse therapy (HDMPT) was applied to the patients.Their symptoms deteriorated and the sellar mass enlarged after a short period of partial improvement.Operations were performed in all the patients.Histology study showed craniopharyngioma with abscess, primary abscess, secondary hypophysitis caused by Wegener's granulomatosis, and germinoma with secondary hypophysitis, respectively.In conclusion, surgery or biopsy is necessary for those who presented with sellar region mass and was suspected to be with LYH, but with poor response or even worse after HDMPT.