Selective excision of adenomas originating in or extending into the pituitary stalk with preservation of pituitary function

When the surgeon identifies an adenoma within the gland and selectively excises it, endocrine-active pituitary tumors are usually cured and pituitary function is preserved. Occasionally ectopic adenomas arise primarily in the pituitary stalk or arise superiorly in the midportion of the anterior lobe and extend upward within the stalk. To determine if these tumors can be selectively excised with preservation of pituitary function, the authors examined the outcome of selective adenomectomy in 10 patients with Cushing's disease with an ectopic adenoma originating in, and confined to, the stalk (four microadenomas) or an adenoma extending superiorly through the diaphragma sella and into the stalk (five microadenomas and one macroadenoma) from an operative series of 516 patients with Cushing's disease. To reach the adenoma transsphenoidally in these patients, the diaphragma sella was incised anteroposteriorly in the midline to the anterior edge of the stalk, the suprasellar cistern was entered and the adenoma was selectively excised using care to limit injury to the infundibulum. After selective adenomectomy, Cushing's disease remitted in all patients. All patients were hypocortisolemic immediately after surgery and required hydrocortisone for up to 21 months. Apart from the adrenal axis, pituitary function was normal in five patients in the immediate postoperative period, including two patients with tumors confined to the stalk and three patients with preoperative hypothyroidism (one patient) and/or hypogonadism (three patients). Three others with transient postoperative hypothyroidism (one patient) or diabetes insipidus (two patients) had normal pituitary function within 7 months of surgery. One patient with hypothyroidism and one with hypogonadism before surgery had panhypopituitarism postoperatively. A patient with a microadenoma located high in the stalk next to the optic chiasm had bitemporal hemianopsia postoperatively. These results demonstrate the feasibility of achieving curative transsphenoidal resection and preservation of pituitary function in cases of pituitary adenomas that are confined to the pituitary stalk or tumors that extend superiorly within the stalk from an intrasellar origin.