A 32-yr-old male-to-female transsexual patient was referred to our institution for evaluation of a pituitary lesion. The patient was diagnosed at age 20 to have a Klinefelter syndrome. After electing to have a female phenotype, the patient had had a bilateral orchiectomy and a transsexual surgery. The patient then started receiving estrogen treatment. During the past 4 yr, the patient has been taking 1.5 mg of ethinyl estradiol and 150 mg of cyproterone acetate daily. For the last 3 yr, the patient has complained of a generalized weight gain of 9 kg, headaches of increasing intensity, and fatigue. There was no change in vision. On physical examination, her blood pressure was 140/80 mm Hg and her pulse rate was 80 bpm without orthostatic changes. A slight bilateral galactorrhea was present. Neurological and visual examinations were normal. The patient had no acromegaloid dysmorphism and no amyotrophy. A magnetic resonance imaging (MRI) scan, performed because of the headaches, demonstrated a 4 mm left sided hypodense pituitary lesion without diffuse enlargement of the pituitary gland (Fig. 1). Hormonal studies were performed between 3 to 10 days after cessation of estrogens.

Mean basal (mean of six determinations performed every 4 h during a 24-h period) plasma prolactin concentration was 365 pg/L (normal,< 15 pg/L), and mean basal GH was 3.6 PLg/L (normal,< 2 pg/L). Plasma GH was suppressed (nadir below 2 pg/L) during oral glucose tolerance test, and plasma insulin-like growth factor I (IGF-I) was 45 pg/L in the range of hypopituitarism(normal, 100-490). T, basal TSH and TSH response to TRH were normal. Plasma LH and FSH were suppressed below 0.5 U/L (normal, 0.5-10). Plasma cortisol showed a normal circadian rythm 24-h urinary cortisol was within normal limits.