Gonadotroph Pituitary Adenoma or Andropause

E. Divaris*^a (Mr), A. Michou^a (Mrs), S. Goulopoulou^a (Mrs), F. Adamidou^a (Mrs)

^a Hippokration Hospital of Thessaloniki, Endocrinology Department, Thessaloniki, GREECE

* divaris.efstathios@gmail.com

GONADOTROPH PITUITARY ADENOMA OR ANDROPAUSE

Efstathios Divaris , Michou Athanasia , Sofia Goulopoulou, Marina D Kita and Fotini Adamidou

Endocrinology Department, Hippokration Hospital of Thessaloniki,

Introduction: Gonadotropin secreting adenomas are not easily recognized in older men because they are clinically silent and are not biochemically different from primary hypogonadism. In addition 20% of gonadotropinomas have negative immunohistochemical staining for gonadotropins. In such cases there is a diagnostic dilemma between non-functioning pituitary adenoma and andropause. We present a case of a male patient with pituitary adenoma, secreting FSH.

Observations: Α male 65 years old, was refered to our clinic, for evaluation of a pituitary macroadenoma which was found after a MRI scan was ordered, due to visual field deterioration. The patient reported frontal headache and erectile dysfunction for a year. Clinical evaluation did not reveal signs of gynecomastia or testicular mass.

Hormonal evaluation revealed high FSH (25.14 IU/L ,normal 1.27-19 IU/L), normal LH (3.59 IU/L, normal 1.2-8.6 IU/L), low total testosterone with repeated testing (258.68 ng/ml, normal <300 ng/ml), high a-subunit (5.5 IU/L, normal 0-0,8 IU/L). Endocrine evaluation of other pituitary axes was normal.

Pituitary MRI imaging revealed an heterogenous, space occupying, lobulated mass (size 4.3 x 3.6 cm) , with signs of optic chiasm compression.

LHRH dynamic test resulted in FSH elevation (30%) and LH elevation (300%). TRH dynamic test did not result in marked FSH or LH elevation.

The patient underwent a transsphenoidal resection. Histopathological evaluation revealed a pituitary macroadenoma, with negative staining for βFSH, ACTH, TSH, GH and PRL. Post surgical dynamic tests revealed lower basic and stimulated FSH values.

Conclusion: In older men patients with a non-secreting pituitary adenoma and elevated FSH, andropause is an alternative diagnosis when immunohistochemical staining is negative for gonadotropins. In such cases, positive immunohistochemical staining for SF1 and elevated, or normal serum inhibin B would support the diagnosis of secreting FSH adenoma.

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The author has declared no conflict of interest.