An unusual case of lymphocytic hypophysitis in a young man presenting with elevated serum IGF-1

Objective. To describe an unusual case of lymphocytic hypophysitis in a man, presenting with an elevated serum Insulin like growth factor-1(IGF-1) level. Case report. We report the case of a 27 year old male presenting with a 2 week history of severe headaches. Magnetic resonance imaging of the head showed an adenoma-like pituitary. The physical examination was normal, laboratory tests revealed secondary hypothyroidism and hypogonadism along with an elevated IGF-1. Complete transsphenoidal resection of the pituitary mass was done. Tissue analysis was diagnostic for lymphocytic hypophysitis. No evidence of a somatotroph adenoma was found. After surgery the patient developed panhypopituitarism and diabetes insipidus. Discussion. IGF-1 is a sensitive disease related marker in acromegaly and corresponds to disease activity. However, it should not be used as the sole marker for diagnosis of disease. Inflammatory lesions of the pituitary gland, such as lymphocytic hypophysitis, can clinically and radiologically mimic tumors of the sellar region. Conclusion. We report an index case of a young male who presented with elevated serum IGF-1 level in the setting of lymphocytic hypophysitis. This case illustrates the dilemma associated with reliance on the IGF-1 levels for diagnosis of acromegaly, since an elevated IGF-1 level in the presence of a pituitary mass may not always be a somatotroph tumor. We propose the differential diagnosis should also include autoimmune hypophysitis.