its best to think about pituitary adenomas as one of three big options, prolactin secreting, ACTH secreting, or GH secreting. The only pituitary tumor that causes osteoporosis and therefore the compression fractures seen in the questions could be a ACTH secreting pituitary adenoma (note: macroadenoma just means that the tumor is >10mm in size). increased ACTH leads to increased cortisol and therefore decreased osteoblastic activity (bone formation) = osteoporosis

Pt has a pituitary adenoma + weight gain + compression fractures.

Prolactinoma = most common pituitary adenoma. However this male patient lacks appropriate symtoms, e.g. decreased libido + infertility. Eliminate choice A.

**Eliminate choice C because this patient does not have signs on increased testosterone.

Eliminate choice E because this pt has weight gain, whereas a TSH-secreting adenoma would cause weight loss.

You are now left with choices A and B.

ACTH-secreting tumors are associated with weight gain + bone fractures. This is because increased ACTH causes hypercortisolism, which has an AE of osteoporosis. This is choice A.

Even though TSH producing adenomas mat also produce compression fractures they are far less common than ACTH producing tumors

This pt clearly has a pituitary adenoma given the bitemporal hemianopsia. The most common functioning pituitary adenoma is a Prolactinoma, so you want to be very sure before not picking prolactin. However, according to FA, "Prolactinoma classically presents as galactorrhea, amenorrhea, and decreased bone density due to suppression of estrogen in women and as decreased  libido, infertility in MEN. No decrease in bone density in men. Thus, given the compression fractures in a male and weight gain, the answer has to be ACTH.