Abstract
BACKGROUND: ACTH secreting pituitary adenomas are rare accounting for only 5-10% of pituitary adenomas. Most often these are sporadic, however there are rare associated familial disorders and genetic mutations. This case highlights a 41-year-old male with an ACTH secreting macroadenoma similar to one found in his brother previously. CASE: A 41-year-old male with no significant medical history presented to the hospital with headaches and visual changes for the past week and decreased libido, weight gain, and cold intolerance for the past year. Physical exam demonstrated left eye ptosis, proptosis, and pupillary dilation with intact visual fields, as well as Cushingoid features including BMI 35.1, abdominal obesity with striae, enlarged breasts and tanned skin. Family history revealed a brother diagnosed with an ACTH producing pituitary microadenoma requiring surgical resection 18 years prior.Brain MRI revealed a 2.6×2.5×3.7 cm sellar mass with optic chiasm compression and pituitary apoplexy. Labs revealed elevated ACTH 708 pg/mL (7.2–63 pg/mL) suggesting a functional macroadenoma, as well as signs of early hypopituitarism with TSH 0.37 uIU/mL (0.35-5.50 uIU/mL), free T4 0.5 ng/dL (0.5-1.3 ng/dL), free T3 2.6 pg/mL (2.3–4.2 pg/mL), prolactin 2.0 ng/mL (2.6-13.1 ng/mL), GH 0.2 ng/mL (