I am a board certified Endocrinologist and manage mostly Neuroendocrine tumors. I have a special interest in this disease and as an attending I routinely treat patients with this specific disorder. I am also a clinical researcher and am currently conducting both NIH and privately funded studies specifically in patients with this disease. A delay in resecting the culprit nodule would result in persistent syptoms, as characterized by sustained elevations in the levels of certain hormones in the blood and urine. Depending on the severity of these imbalances, the consequences could include fatigue, proximal muscle weakness, easy bruisability, weight gain, high blood pressure, diabetes, lower extremity swelling, osteopenia/osteoporosis and fractures. This imbalance also predisposes patients to potentially dangerous infections. If the presence of a liver nodule had been noted on the original CT, the physician’s clinical suspicion for a non-pituitary cause of this disorder should have been increased and further tested, likely including a biopsy of the lesion could have been considered prior to “exploratory” neurosurgery, given that Bronchial Carcinoids are the most common cause of this particular form of the disease. However, it should be noted that biopsy is not routinely performed for the purposes of identifying the culprit tumor in this disorder, as the tumors are typically very small and unlikely to be diagnosed by taking a random sample of the pituitary gland. In cases where physicians are trying to determine if this disease is being caused by a tumor that is in the pituitary gland (but not visible on MRI) or ectopic, a procedure called inferior petrosal sinus sampling (IPSS) is typically recommended prior to pursuing exploratory brain surgery. Exploratory Neurosurgery is sometimes pursued, but usually only when there is a contraindication to IPSS or if IPSS is not available. Typically when we care for patients we pursue the least invasive tests first, in order to minimize morbidity. When no tumor was visualized on the brain MRI or chest CTA, a more routine evaluation for this patient would have consisted of IPSS. A negative IPSS would have indicated that the tumor was not in the pituitary gland, and at that time more extensive imaging studies ? like PET scans or octreotide scans, would have been performed to locate the tumor. At that juncture the lung lesion would have been identified and subsequently resected.